Its not easy question.
It depends mainly on structure of increasing blinds.
I usually play very tight when have 30+ blinds, am looking for spots only if am
sure that am not beaten, i dont steal much, when am at medium stack (u can say its low) 15-30bb i try to take more spots with hands like K10s,KJo,A9s,A10o on all positions, QJo,Q10s,J10s,109s,98s at late position, at low stack am not trying to double at first good card, prefer not to give up easy, am raising 2,25-2,5bb or pushing, then my range is 55+,A9s,A10o-AKo,KQs.Good luck and see you at the tables!