To an UG to UG+2 raise, I would probably fold JTs-76s. At what position of the raiser is it OK to call the raise with these hands?

For a pocket-pair I would call in any position if the effective-stack >= 20 x raise.

But for suited-connectors, it seems much more complicated (there's conflicting advice on this).

Someone somewhere said if you play fit-or-fold on the flop, then calling EP/MP raises with medium suited-connectors is suicide.
But if you're a really good postflop player and can float/bluff well, then it's OK to call any preflop raise with these hands.

But what is the advice for the average recreational player?

Just fold the majority of them and 3bet or fold the better ones in position. And by 3bet or fold I mean mostly fold.

Are you playing live, or the lowest stakes online, where there are likely to be several callers and no squeezers, or is everyone a nit that's waiting for aces, or are you playing in tougher, more aggressive games?
Also, your position is important. You can't flat many hands in MP if there are 6 players still to act. You can call more often on the button if half the table has already folded. Most SCs and small pairs are not very profitable as calls though. People remember the occasional big pots they win with T9s or 44, but seem to forget about the much larger number of pots that they lose.

If someone opens for 2BB and the effective stack is 100BB, JTs looks way more appealing than if the open raise is 7BB and the effective stack size is 50BB.

generally if opened for a raise in early position the only time to play them is the hand you want to lose so you can go home.

everyone is looking for a reason to play. look for reasons not to play.

Maybe not vs. tight early or too big raises but if you either get and tend to get so good odds that you can fold one pair on the flop or the post flop play is reasonably predictable. Personally, I am happy to donk off as much money as my opponent's on average do.

Since you need to hit those pretty hard and have good implied odds I lean towards calling this in the BB if the raise wasn't too high and there are several callers.

It also depends a bit on the initial raiser. If he's someone who plays fit-or-fold or can make 'tight folds' on later streets then there's reasonable chance to take AK, AQo or similar away from him. So for someone like that I might call or reraise on the button to isolate because fold equity goes up.

But mostly it's a fold.

Have to interject the famous 'this depends' disclaimer. It's better to call than to raise against players who either 4B a lot, or simply don't fold to 3B very often and are stationy post-flop. The purpose of a 3B is to increase fold-equity both pre and post-flop, so if we're up against a villain who rarely yields fold equity, then we want to see a cheap flop and try to go the implied odds route with position. Just remember to balance your calling range with nutted pre-flop holdings so that you don't cap yourself. And I'm talking more to OP than you, as I'm sure this is not news to you!

The best advice for the average recreational player is that you should play fewer hands than good players and most good players are going to be tight.

There are so many variables to consider, such as if anyone else has already called the raise and how many callers are you likely to get behind you if you call. There are times when I will happily call with such a hand UTG+1 against an UTG raiser because I expect six callers and light re-raises behind me because I know my opponents well enough to know how the hand is likely to play out.

Suited connectors are speculative hands that rely on implied odds to be profitable. So, you want the raiser to be someone who overplays top pair or better when he is beat or you want the raiser to be someone who gives you plenty of opportunity to bluff him.

Against my regular opponents at my home casino, I call with these hands sometimes but not all the time, just often enough so that they know I might have these hands, allowing me to bluff on boards that aren't high cards. When away from home, I am much more likely to fold.

If you are an average recreational player and your goal is to maximize your winnings, then fold. If you are there to have fun and don't care if you lose, it's not the worse thing in the world to call with these hands, but you should have an idea of what scenarios you plan on bluffing in.

as the implied odds get much bigger your hand gets worse. you have to hit absolutely the best end of your straights to break someone that can play. and he cant be very good either.
you are much better off with a pair until your very deep. and only a couple hands like 5,6
when very deep.

You have bigger implied odds against bad players than good. You should be more willing to call a raise with suited connectors against a bad player than against a good player.

Against a weak-tight opponent, your profit is usually going to come from him letting you take the pot away from him too often, so you are looking to win a series of small/medium pots and not interested in playing for stacks since he usually has the nuts, or close to it, when he is willing to commit all his chips. You can play a lot of hands against a guy like that. You shouldn't play every hand, but suited connectors are a better choice than unsuited disconnectors.

all true. answer for it all is only in special cases where you have good reason and not in general trying to hit something and have something good happen.