For some time now, I have been debating whether to provide advice on this topic for two main reasons. First, I do not want to give you, the reader, the impression that playing an ace with a small kicker is a good thing to do routinely. On the contrary, playing this type of hand all the time is a sure-fire way of losing all your money. Second, it is a tricky topic to give precise advice about because so much depends on your opponents. However, I think that there is some profit in playing these hands when the situation is right and what I would like to do is throw some opinions and points-of-view at you to ponder.
Some players have the view that an ace with a kicker below a ten is an automatic fold. This is a sound approach, no doubt about it. But in my opinion, you will invariably run into two problems with this approach. First, some (more observant) opponents will be reluctant to give you any action when an ace appears on the flop and you come out firing. They will assume that you have a strong kicker to go with your ace. Second, there are so many pots where an ace in hole will win the pot, irrespective of the kicker. Sometime, you don't even need a pair to win the pot. I have several pots where my opponent raised preflop behind me with Kd-Qd and I called that raise (after limping) with As-5s. Neither of us improve, but I will walk home with the money. In my view, when you miss these sorts of opportunities, you are effectively missing out on profits.
REALLY BIG CAVEAT ONE : DON'T DO IT IF OTHER PLAYERS ALSO PLAY ACE SMALL KICKER
Let me start with two really big caveats. The first one is "don't do it if your opponents routinely play Ace-anything." Don't even consider it because it effectively becomes a rat race: you have A-4, he has A-7, she has A-3 If that's the kind of table you're at, forget play ace with a small kicker. This is exactly the sort of table where it is perfect to wait for AK and AQ.
In point of fact, Ace-small kicker works best on very tight tables, where players have patiently waited for KK or QQ, finally got it and will refused to fold when you have A-5 and you bet on a flop of A-6-3.
REALLY BIG CAVEAT TWO : NOT IN MULTIWAY POTS
To put it simply, I wouldn't play Ace-small kicker in a multiway pot. I prefer small pots. In multiway pots, there is a greater chance that opponents are in there with A-9 or better. Best to stay out and wait for short-handed pots, where there is less chance of being beaten by a marginally better kicker.
BE SUITED WITH STRAIGHT POTENTIAL
To offset the disadvantage of playing Ace-small kicker, you need to have other ways to win for "insure" yourself. Being suited is the best start. If you flop a flush draw, your kicker is of no significance as you will have the nuts if you complete your draw.
Similarly, I like to have straight potential. A-3, A-5 and so on gives you the ability to make a wheel another form of insurance. But I generally fold hands like A-6 and even A-9. Many of you may regard this as illogical because I'm effectively throwing away ace-mediocre kicker, but playing ace-small kicker. But if your opponent has A-10 or better and an ace appears on the flop, it doesn't matter whether you have A-8 or A-4, does it? I would prefer the latter preflop because it has straight potential that the A-8 doesn't have.
READING PLAYERS IS THE MOST IMPORTANT PART
I would go so far as to say this: if you are not terribly good at reading your opponents, don't read any further. Many players either have difficulty reading opponents or do not act on their reads, even though their reads are usually correct. They can still be successful at poker, but they will never reach great heights I suppose. So if you fall into this category, don't even consider playing ace-small kicker because it is definitely a hand where good reads are absolutely critical.
Here is a classic example that I encounter. I limp in a late position with A-5 suited and then the big blind raises with K-K. I call along with a couple of other opponents and the flop comes A-9-6 rainbow. The big blind then comes out betting almost as if it's automatic because he raised preflop. Many opponents here will fear AK, AQ or AA. However, some players will routinely bet this pot from a weak position with KK or even 10-10 and because of that, I will actually raise the flop behind him, even though most players will probably call or fold in the same situation.
This goes to show you how important reading opponents becomes with ace-small kicker. You need to know your opponents tendencies. Specifically, you need to know whether your opponent in that situation would bet KK or QQ on a flop containing an ace from an early position after raising preflop. Furthermore, you need to put him on a hand by observing his reaction to your raise on the flop as that reaction will effectively dictate your play thereon after. If this seems beyond you, it's nothing to be embarrassed about and you are probably better off waiting for stronger kickers.
AGGRESSION ON THE FLOP IS EVERYTHING
If the flop comes A-9-6, an opponent with AK bets and you then raise, he will usually reraise you. Alternatively, he may appear to contemplate a reraise, but then call and subsequently give you the impression that he may attempt a check-raise on the turn. In either case, he has you beat. But which ever reaction you get, you draw out these reactions by raising him. If you call, he has little information about your hand and you have little information about his. Therefore, aggression on the flop is the best way to 'test' your opponent. Don't be afraid to give away your hand.
PLAY THE FLOP WITH A HIGH DEGREE OF DISCIPLINE
The moment you realize that you are beat, fold immediately. I've had hands where the main opponent bet, I raised and he reraised and I folded straight away because I knew that he would never reraise in this spot unless he had an ace with a respectable kicker. As a result, I will not call his reraise on the flop. Many other players in the pot may be frustrated because (a) your play doesn't seem to make any sense to them; or (b) you have trapped them for extra bets and then folded. My view is simple: you're not there to please everyone at the table; you are there to make yourself money or save bets if necessary. If they get stuck calling raises and reraises, bad luck to them they probably shouldn't have been calling in the first place anyway. You concentrate on what you want to achieve and if you raise for information and get the information you wanted, your ploy has succeeded, even though it really hurt the other players in the pot.
IF YOU DECIDE TO PLAY, PLAY ALL THE WAY TO THE END.
If your instincts tell you that you have the best hand on the flop, don't fall into the trap of second guessing yourself on the river. I would need to catch an unmistakable tell on the river to give it up. Therefore, if you decide to play on the flop, generally look to go all the way to the showdown, unless something goes horribly wrong (for example, if the board contains four cards of the same suit by the river). It essentially comes back to sticking with your first impressions because they are usually correct. The worst way to play this hand is to play it to the river and then fold.
A CALL OF YOUR RAISE ON THE FLOP IS NOT ALWAYS BAD
As you get better at reading players, you will be better able to judge whether your opponent has an ace in the hole on a flop of A-x-x. I have had situations where I called a preflop raise from an opponent and the flop came As-10s-8h. He bet and I raised. The moment he called, I read him perfectly: I knew he had a pocket pair below aces and he was simply calling because he thought I may have a flush draw or straight draw. I felt comfortable betting the whole way because I knew I was in front and I extracted the maximum.
I suppose the point of this little story is this: if you get that 'feeling' that you have an opponent beat but he still calls your raise on the flop, you should stick with your first impressions and bet away at the turn if he checks. Don't automatically assume that he is conspiring to check-raise you on the turn. If he does, well that's an easy fold. If he doesn't and you are in front, you are turning good profits where other players are missing out. But all this ties in with the fact that you need to know your opponents pretty well and have the ability to make good reads on them.
But certainty is the key: if you have some doubt about your opponent's hand and you need to slowdown fast! One technique that can work fairly well when you are uncertain is checking the turn behind your opponent. If the opponent checks again on the river, you can probably go ahead and bet. Strangely though, the situation is altogether different if you check the turn after raising the flop and your opponent comes out betting on the river. In this case, I (more often than not) think that I'm beat, unless I know that my opponent will routinely try to steal the pot with a substandard hand in this situation.
POSITION IS IMPORTANT
For reasons that you can learn from any good poker book, position is important. However, when you hand is marginal, position is much more important. Playing Ace-small kicker from an early position is "playing with fire." Don't do it. You don't necessarily have to be the button, but playing this type of hand up front is simply too dangerous mainly because it is too easy for someone to either (a) move you off the best hand; or (b) control how much profit you make when you have the best hand by raising you for free cards.
OUT OF THE BLINDS
Many of the examples I brought up discuss situations where you have the luxury of position. But many times, you will be . "forced" to play these sorts of hands from the blinds especially when they are not suited or have no two-card-straight-potential (A-2, A-3, A-4 or A-5). In other words, you be forced to play a lot of hands like A-6 and A-7 from the big blind because no one raised.
Approaching this is not always easy for two reasons. First, several players will limp with hands like A-9 and A-J without raising and because of that, you are more vulnerable. Second, if you bet your hand, several opponents with hands like A-10 will simply call you the whole way, rather than raise.
Nonetheless, I almost always bet the flop straight up if I catch an ace. A bet from an early position appears to many as much more threatening than a bet from a late position. I find that if the flop does not have any obvious draws (eg A-8-2 rainbow), most reasonable opponents will fold the flop. Furthermore, the opponents who call will probably have a pair of aces or a pair of eights. Therefore, you have boiled down the situation significantly. On the turn, I will probably bet again if I am fairly certain that I am in front and to keep my opponents on the back foot. But if I get callers on the turn, I will invariably check the river and on most occasions, none of my opponents will bet into me unless they have AK or two pair.
There are three main advantages to this approach. First, players will not get tricky with you on the river if you play your hand this way. You have shown enough strength to indicate to your opponents that you will probably call the river if they bet so they know a bluff would virtually look like a 'sucker' play in this spot. So if they do bet, you're almost always beat! Second, you are maximizing profits for those occasions where you are in front (which may be more often than you think). Third, even if you lose some hands here and there, your opponents will see that you occasionally bet A-7 on the flop and turn. In turn, they may give you some action on those occasions when they have hands like AJ and you have a hand like AK. It can really help that 'loose careless player' image that you want, even though you are playing a relatively tight game by and large.
YOUR OPPONENT DOES NOT ALWAYS HAVE AN ACE
I would like to finish on this point. Many experts advocate that AK and AQ plays, but Ace-anything else doesn't. It is true that folding AJ preflop can be 100% correct in specific situations. But in many cases when an ace appears on the flop and you have an ace in the hole, there is a reasonably good chance that you are the only player in the pot with a pair of aces.
The reason experts write books about playing AK is because it is a hand that almost plays itself and therefore, it is not difficult to explain how to play it. Moreover, experts know that beginners have difficulty reading players and therefore, they provide you with examples of hands where you don't need to rely so much on reading players. But you will find that, in poker, you can play more hands and open up your game much more when you are good at reading players.
More to the point, if the flop is A-Q-6 when you have A-5 suited and you bet, don't automatically conclude that the caller must have A-10 or better. Many times, I have bet in this situation and when my opponent called, I put them (correctly) on K-Q or Q-J and continued to bet.
So when you flop a pair of aces in a normal pot, you will often find that you are the only player in the pot with an ace in the hole. But conversely, it's fair to say that in a large multi-way pot, you more vulnerable and should tread carefully in fact, you should not get involved in the first place.
To wrap up, I would like to reiterate that certainty of your opponents' hand is the big key. I understand that you are never 100% certain; no one ever is! But there is a big different between "I just knew he had pocket Queens or pocket Kings" and "I think he may have a pocket pair below aces." With the former, bet all the way if that's how you feel. With the latter, I may just check the turn and/or river and hope for a cheap showdown. I won't over-commit myself when I have doubts.
But as mentioned previously, if reading players is not your forte, I would not bother playing Ace-small kicker at all. Wait till you have acquired this skill.