Each pocket pair is different, and I will say, that the smallest ones tend to be overvalued by a lot of poker players. Its pretty common for people to feel, they always have to see a flop with a pair, and that is certainly not the case.
When I played cash games on
pokerstars and began running filters in my database, one of the first things, that jumped right out at me, was, that I was losing money with 22-55. And after discovering this I naturally began tightening up. Generally open folding these
hands from early position at full ring tables and not mindlessly taking on every single set mining spot.
Specifically with setmining the issue is, that people dont always spew as much postflop, as we would ideally like. Again talking about cash games, most decent players dont stack off a single pair in a single raised pot for 100BB, or at least they dont do it very often. And this mean, that even when we get that perfect situation, where we flop a set, and someone have a big overpair, we still dont get their entire stack.
And then of course there are those spots, where we get coolered with a set over set, or someone complete their straight or flush against us. Even flopping a set dont always mean, we win the pot. So when we play small pairs it often need to be with some other ways to make money then just flopping a set and getting paid.
In tournaments there are also lots of situations, where stack sizes are just really unfauvorable for small pairs. We are to shallow to setmine and to deep to jam preflop. In those situations it can be fine to open fold a hand like 22 even on the BTN, if we have ICM pressure and aggressive 3-bettors in the blinds.
Hands like 99-JJ on the other hand should definitely be solid winners in our database, and they should always be opened. When people find these hands difficult, its more about the fact, they often make a medium strong made hand, and this kind of hand is somewhat tricky to play. We need to have solid postflop skills and understand concepts like pot control and showdown value and defend well against aggression, when there are overcards to our pair on the board.