We all know that all too common saying in NL Holdem....."I'm all in"! I love going all-in when the situation calls for it. It's one of the ingrediants that makes the game of NL Holdem the game it is. Simply the Best IMO.
Basically in no limit tournament poker, going all-in is common. In regular no limit ring games it isn't unless you have just a short stack left. I recommend buying in for the full amount and keeping it at that level or above the entire time. You don't want to play a $50 NL game and then bleed out $25 and just have $25 left on the table. If you get a great hand, you want to be able to double through for the full amount.
There are two scenarios for all-in's. The first scenario is when you are doing the all-in bet. That's a good thing. That means you want all your money in the middle.
The second scenario is when you aren't the one putting all the money in the middle. To decide whether or not you are going to call their bet, you need to ask yourself a few questions.
How much is it going to cost me?
How much is already in the pot?
Is this guy for real?
For an example...Let's say you have AK and flopped top pair and bet it down the whole way and on the river the guy check raises you all-in. Let's say the pot is $100 now and it will cost you another $25 to call. That's easy, you call. Let's say it costs you $50 more. Now I'm starting to think. If it is any more then that then I probably would have a hard time just calling with one pair unless I thought this guy either was a wild player, didn't know what I held, or if I had seen him do something similar before with a marginal hand.
So my all-in rule of thumb, is just to asses how much of a hit I'll take to see the showdown and compare that to the size of the pot. Obviously the stronger your hand is the easier it is to call. It is impossible to make yourself immune to paying off hands in no limit holdem. Sometimes the pot just is too big to fold and you have to put the rest of your chips in. That's NL poker.
PKRBABY
Going All-in 
