There are many Hold 'em starting hand charts available. There's at least two available here on CardsChat as well, not counting ones that have been posted in the forum. There are two things these all have in common: They're incredibly useful for a beginner to memorize, but they're worthless to an experienced player.
So let's talk preflop play for awhile. If you've played Hold 'em at all, you're bound to know that pocket aces constitute the best starting hand. Any starting hands chart you'll find will reinforce this: A-A is listed as a raising hand for all positions. So is K-K, actually. This makes sense; they're both very strong starting hands, because they can actually win quite a few pots unimproved. A large pair like that is a huge favorite against even several opponents. So it makes sense to raise it.
What about AK? That hand is also recommended for a raise in every position - but that's kinda weird, isn't it? It's not a made hand. It's only ace-high, and you're unlikely to win the hand unless you actually pair up somewhere down the line - yet the recommendation is to raise it. Why is that? And a hand like 5-5? That'll almost never be good enough to win pots with, unless I'm really lucky and spike a third five on the flop. But that happens very rarely - can I still make money from playing it?
The observant readers - and I hope that means all of you - may be guessing where I'm getting with this, at least in the case of the fives. Let me introduce you to the two concepts that guide preflop play: Equity and Implied Odds.
Equity can be explained as your share of the pot. Every hand you are dealt has a certain chance to win before all the cards are out; even if someone has pocket aces on the same deal, your 72o still has a small chance to be the winner. This percentage is called your equity - the amount of the pot that you in some mathematical sense "own." This equity will change as cards are being dealt, of course - if you have 72o vs. AA preflop, but you flop two pair, your equity has shot through the roof - you may now suddenly be a favorite to win, whereas before the flop, you were a big dog! With a large equity, you figure to win more than your share of the money that's bet, so raising is a good idea.
Let's look at those pocket aces a little more closely. Every starting hands chart recommends you to raise with them, so let's examine why: If you have pocket aces and you're up against 9 other players (whose hands you have no information on yet, let's say that you're UTG), your average equity will be 33%. This is how well aces fair against 9 other hands that call all the way to the river; ~30% of the times, the aces win. A bit of a bummer, perhaps, that your aces won't even win a majority of the time, but at least you have a better chance of winning than anyone else at the table. But also keep in mind that it's highly unlikely that everyone else will call all the way to the river, so perhaps your winning chances are a bit better than 30%.
But what if everyone calls anyway? Then you're surely in trouble - 7 times out of 10, you won't win the hand.
Look here: 3 times out of 10, you will win 20 bets (the big blind + your raise), and 7 times out of 10, you will lose 2 bets (your raise). A win of 60 bets, and a loss of 14. That's a net win of 46 bets! That's HUGE! It's true that you won't win more than half the time, but that's okay because you're paying considerably less than half of the money going into the pot. This is why we raise with AA: It has a huge equity preflop, and anyone who calls you is paying you more than they're winning. AA is so likely to win the pot in the end, that you can safely raise now and expect to show a profit in the long run. The same, of course, holds true with KK and QQ.
But what about AK? This so called "drawing hand." It's true that it's considerably weaker than AA, but it's far from helpless. And even against a large field of opponents, AK will still win more than its fair share of the pots. You flop a pair on average once every three times with AK, but for the same reason that AA is okay even if it only wins 30% of the pots, AK is okay even if it only gets help once every three times. It will simply win more than its share of pots, even against many opponents. Especially when suited.
The lesson here is that with hands that have strong equity, you should raise preflop. How strong a hand's equity is depends on what it's up against, of course, and you can never be quite certain of that. In one specific case it doesn't matter: If you have AA, you can always raise safely. KK, on the other hand, is in big trouble if it finds itself up against pocket aces, but the risk of that happening is so small that as a general rule of thumb, you should always raise with KK preflop, as well. However, with hands such as 55, do they really have a big equity vs. 4 other opponents preflop? Hardly. In fact, they are probably pretty far behind. But they can still be played profitably, and for the same reason that suited connectors can. Read on.
Yes, 55 is a good hand to try to get a cheap look at the flop with. The odds against you flopping a set with a hand like 55 are pretty bad; about 7.5-1 against. So looking at equity alone, a case could be made to raise 55 if you have 9 other callers (since you expect to win with a set, which is 7.5-1, but you're getting 9-1 on your money). Not a terribly strong case, but still. However, good players will get in with these hands even if they have considerably less than 7 opponents, despite having bad equity, because while they have to pay to see the flop, the reward they get when they hit it hard is more than enough to show profit. These hands are called speculative hands. This is implied odds at work. The pot may only be offering you 4-1 on your call right now, but then you only need to make up a few more bets on the flop and beyond to be a winner in the long run. With loose opponents, this is easy. And in good position, this is even easier.
A similar argument can be made for a hand like 98s, where it's very unlikely that you have the best hand preflop (or even positive equity) but it's very likely that you can get paid off bigtime if you can sneak a peak at the flop cheaply and hit it hard. This concept is not difficult to understand, of course, but it's still misapplied by beginners all the time. For instance, limping with small pairs in early position - this can be a bad idea. It's true that you may hit a set, and it's possible that you have the implied odds to make up for the one bet that you put in now, but what if you get raised preflop, and you end up being only three to the flop?
All of a sudden, you've paid 2 bets to win 6. Now, if you hit your set, you have to make up another 10 bets on the later streets - on average. Unless your opponent also flopped a strong hand, you've just made a costly mistake. But what could you have done differently? You had a pair of fives, and it's a good hand, and it was bad luck that one of your opponents raised - wasn't it? Sure was. But this is why position matters with speculative hands. If you had been in later position, you would have seen his raise before the action got to you, thus allowing you to make a correct fold. Of course, position matters for a second reason as well: If you do flop a monster, you're much more likely to make the most money from it if you can have the raiser to your right. Having position means that your implied odds go up, and speculative hands thrive on that.
So now we've covered the two concepts that apply to starting hands. Since the average equity for a hand is usually known, and since you can somewhat easily figure out if a speculative hand is worth playing from a certain position, it's simple to see how the starting hand charts are constructed. What I'm hoping to achieve with this article, however, is to get you to understand the underlying reasons for why the charts look the way they do - because armed with that understanding, you will be able to take it to the next step: adjusting to the table you're playing.
Let's revisit 55. Most charts will tell you to toss that away in early position, and I've already explained why. But what if you've played for the last hour at this table, and you know that no one (except for you!) raises preflop, and that the flop usually gets 5-6 callers. Should you still toss it? The chart says yes.
But I hope you now say no.
The value of the speculative hand is there! You will get in cheaply, and get almost immediate pot odds for hitting your set. You can be pretty confident that you won't be raised after you limp, so that's safe too. Sure, you'd prefer to be in better position to milk your set if you hit it, but with so many people seeing a flop, you will still be paid more than enough to cover the times you miss.
These adjustments aren't necessary to make a profit, if that's all you want. In fact, adjusting to the table is difficult, and requires awareness and reads, both of which will require a great deal of focus. But a player who will not adjust his requirements to the table he's playing is missing out on a lot of potential profit. And to show you the extreme case of the other side, let's look at a hand I played at a $2/$4 full ring limit hold 'em table a few months back:
I had AQo on the button. This is a strong hand. The first two players off the big blind fold, but then the third player - who is very loose - raises. Now, ordinarily, this would not mean much to me. Loose players are like that after all. But then I noticed what pokertracker had to say about him: In the 350 hands that we had played together, he had raised only once before: And that was with pocket aces. When the action came to me, I laid my AQo down. Without a read on him, I would have 3-bet here every time, but I trusted what I was told: This player only raises preflop with the extremely big hands, and against those, my AQo was a huge dog. At showdown, he showed KK. The flop had come Q-high, which would have given me top pair, top kicker, probably costing me at least $20. In a game that measures profit by a few big bets per 100 hands played, saving 5 big bets on a read is pretty great.
Now look at a starting hands chart again. Look at the suggestions they give for early, middle and late position. Do you see how strong equity hands are suggested for raises? Do you see how speculative hands try to get in as cheaply as possible? How you open up more and more speculative hands at the late positions?Hopefully, you'll be closer now to understanding why that is. With experience, you will also learn how to adjust to different conditions at the table.