How does stack deepness affects how to play?

I mean, the basic rules.

Stack depths affect the risk versus reward ratio of many decisions in NL. It doesn't have a significant effect in limit except if someone has only a few bets left.

The simplest example is when you move all-in. Deeper stacks in relation to the size of the pot mean your opponent has to win more frequently in order to make a profitable call. If you are bluffing, you are risking your stack for the amount in the pot, so deeper stacks mean your opponent must fold more frequently for the bluff to be profitable.

Second, if you bet or raise a smaller amount than all-in, this is much more threatening if you have a lot more chips you can bet on the next streets.

Third, if you are considering calling with a draw, you should consider the implied odds. The true reward when your draw hits on the next street is often much more than the pot, since you might expect to win additional bets, particularly if your draw will be completed by a card that does not look threatening. The stacks provide a limit to your implied odds.

When the stacks are under 40 times the big blind, in general, you should be aiming to make a good hand often, such as top pair with a good kicker or an overpair. When the stacks are over 80 big blinds, you should aim both at those hands and at rarer stronger hands like sets, straights, and flushes. When the stacks are under 10 big blinds, you often want to move all-in preflop to attack the blinds and any limpers.

The depth of your stack in relation to the big blind and the depth of stacks of the other players (often called Effective stack size) at your table, affects your play to a huge degree.

When your a shortstack you reduce the effect of the other players big stacks i.e they don't have the potential big hammer behind, the better players won't have as many rounds of betting to out play you. Being a shortstack also reduces the type of hands you can play for implied odds. Your betting as a shortack may be Preflop raise, then call allin pf, or allin or fold on the flop quite often.

Deepstack poker means that your betting now will have potentially many more actions on more rounds, meaning
you will have many more chances to make an opponent commit an error or make one your self, you will trying to control the potsize more, playing big pots with big hands and good posistion and trying to not get stacked with good
but not great hands.

"Very basic" basic rules of adjusting with stack size.

Low stakes examples - 10NL Cash

You're in BB w/ A6s and 150BBs, button open raises to 3.5BBs, he has 30BBs. The main reason you'd call this hand is to hope to flop trip 6s, or to flop a flush or strong draw. This is too unlikely compared to the maximum upside if winning all of your opponent's money. Although he could be raising with some holding like 9Ts, you fold.

Now take the same situation, except villain also has 150BB stack. Now you could call to try to win his stack - the probability of your ideal flop hasn't changed, but the potential upside is now more worth the risk. Aggressive players may even 3bet this exact hand PF with the intention of folding to a shove PF, and if he just calls, bet/folding the flop. Their goal is to make the pot big enough to where villain DEFINITELY loses his stack when you hit your ideal flop.

Another big difference is when your stack is deeper, opponents will be calling with pocket pairs more often to set-mine and win your stack. So you have to always keep in mind that when you raise, you have to play post flop in a way that the PP folks are being overly optimistic about their implied odds.

Those two are the biggest, but now that I think of it, the PP consideration is probably most important.

ty vm for the answers