[RemyXO]

I open-raise with TT and 99 in any position, but I play at more aggressive tables. Sure, they don't win as much as higher pairs, but they are pretty profitable. Raise them and play some postflop poker, aight?
Typically, if you get callers, overcards fall and you can't take it down with flop c-bet, you can give up and move on. But it depends ... post TT-99 hands that give you trouble.

I can three-bet with TT-99 in middle-late position depending on the villain. Certainly 3-bet in blind steal/blind defense situations.

Smaller pocket pairs are typically only playable for set value. You are 7.5:1 to hit your set. Limping first in from EP/MP with small pairs is just asking for trouble. Typically, I overlimp 2 villains if I am holding 88-22, overlimping one does not seem to be +EV.

If I am opening in OTB, CO, SB positions, I usually raise all pairs, unless the blinds are very aggressive.