I generally don't 3 bet unless I have a monster hand or I know the raiser is loose player. Once I know the player is loose I start 3 betting wider. 4 betting gets a little tricky. 4 bet bluffing
against a calling station is just lighting your money on fire especially out of position. I'd only save 4 bet bluffs for thinking players that like to 3 bet light.
Good 4 bet bluffs include A suited, K suited hands (Blockers to AA/KK/AK combos), some suited connectors, and some pocket pairs. If villain 5 bet shoves and you know they're not a complete maniac it's a fold. My 4 bets in cash are in the range of 20-25 BBs so at max I'm only losing quarter of my stack to failed bluff attempts.
Rarely do I engage in 4 bet leveling wars at the micro stakes though. Usually I'm running into AK, QQ+ at that point. So leveling with 4 bet bluffs is kind of higher level tactics. Don't level yourself at the 2/5/10 NL stakes