Recently I started folding small pocket pairs (55-22) from BB, but want to check if it is a mistake.
Made a bit of analysis of my cold calls preflop with pocket pairs.
EV of flopping a set ~14bb, fullhouse no trips on board ~15bb, quads ~20bb.
EV of flopping set is pretty much the same vs UTG, MP, CO, SB but vs BTN it is lower - only around 10bb.
EV of flopping sets with 55-22 is the same ~14bb.

Overpairs:
77- 0bb
88 1bb
99 1.5bb
TT 2.5bb
JJ 2.5bb
QQ 0bb (I think must be around 3-4bb)
KK 5.5bb
AA 6.5bb

Flopping a set or better happens ~11.5% of the time. So If I will not bluff when miss, I need to call preflop no more than 14bb * 11.5% = 1.6bb

Checked my cold call vs 1 raiser with pockets:
55-22 are only plus EV on BTN (0.6bb) and BB (-0.5bb).
99-66 are plus EV on every position (0.45bb overall).
TT+ plus EV
What's funny - found that sometimes I call KK-QQ on SB and BB and they are minus EV calls. Slowplay is bad.

When calling a 3-bet situation is different
EV of flopping a set or better ~35bb.

Overpairs:
99- minuses
TT 2bb
JJ 6bb
QQ -2bb (something bad about QQ is happening obv)
KK 30bb
AA 10bb

So If I will not bluff when miss, I need to call preflop no more than 35bb * 11.5% = 4bb which is not the price you mostly pay in game...
Checked my call 3-bet with pockets, TT+ are plus EV, 99- minus EV.
AA 30bb
KK 10bb
QQ 2bb
JJ 3.5bb
TT 0.5bb
99-66 -0.9bb
55-22 -2.2bb (a bit better than folding if we open x3)
Positional data has almost no difference which is kind of unexpected.