Let's say I'm on a button and I get 3bet by the blinds rarely (Small sample)

Should I still be defending wider? Even though I don't think I'm getting exploited by their 3bets since they're not 3betting me enough to do so.

To be more specific, over 80 hands I get 3 bet first time. Would it be necessary to start defending even though I'm up against a super strong range or is making exploitative folds the way to go?

Another question: Their sizing is 3.5x and the 3 bettor I'd not consider a good reg, is flatting all pocket pairs profitable in that spot knowing that he'll get the money given both of us hit their hand? Example: 55 vs AA on 952r. My sizing 3x since player pool is weak.