Please feel free to point out and correct any incorrect terminology I might use.

My questions are regarding fullring NLHE.

O.K if I uderstand correctly, the princible of set value is when you play a pocket pair that is either low or probably dominated with the hope that if you catch the set your implied odds justify the move. O.K,1 in 8 flops will trip up pockets so I figure as long as you make at least 10 times your initial investment when you do hit it (allowing for the times when your set gets beat) then its +ev am I right? or is it more than 10 times?

how deep does your opponent have to be (assuming its a single opponent on a fullring game) to justify playing for set value?

What about in early positions? eg. If mr TAG opens utg with a 3 bet and you are utg+1 with say pocket 8s, is it ever correct to play for set value? or does the possibility of someone behind re-popping make it -ev?

Any help with this theory would be appreciated.

I think you're looking at low to mid range PP all wrong my friend.

The only time you're behind with that type of hand is when your opponent has a bigger PP.

With that being the case, you're on the right track with implied odds.

I prefer not to play those small pockets in a limp/call out of position scenario. I'm setting myself up for a check/fold flop to an opponent in position.

The only time I would feel that it's a solid play to limp call a small PP is when your well positioned opponent is someone who over values hands. If this is a villian who thinks AJ/A10 is the nuts on an A 8 5 board, then you might want to think about taking them head on with 55.

It can also help if your opponent has a deep chip stack and would likely double you up should you hit a set. You implied odds are good enough at that point to call a raise of 10% of your stack.

Now onto playing any small PP to a flop with mid to late position. The only time I limp small to mid PP late is in pots where there are a lot of other limpers. Typically with a 3-5X BB raise you're still going to end up having to play 3-4 handed. In that scenario you NEED to hit a set to win a pot. It is highly unlikely that 1 of your 2-3 opponents will not outflop you.

If there is only 1-2 limpers, a 3-5X BB raise will likely get you down to heads up most times, but sometimes you'll play 3 handed. You've now kept the pot size medium on the flop and can sometimes take it down when your opponent checks to you.

Keep your table image in mind when making these raises with small to mid PP though. If you show down a wide range of hands you will likely get more action than you'd like with these hands, and if you play timid, you'll have a hard time winning those pots. If you only show down premium hands though, you will probably take some of these down pre-flop with position because opponents will just surrender their BB or limp to you.