online time I'd alter my frequencies are:

-when good competent players are in the blinds that 3bet with proper frequencies
-when I'm in the CO and the BTN is very loose
-when I'm in the SB and the BB is very loose

otherwise, fire away

perfect time to steal:

-from BTN when blinds are awful and passive
-from CO when BTN is a nit
-from CO/BTN when all players behind us are nits

This is why seat selection is more important that table selection in my mind. If we can find a seat where the players are on our left are really passive and hopefully tight it makes life much easier. We can steal the button a ton and just rape their blinds. Also, that makes the likelihood of the fish being on our right, which is nice.