Just make timer based class defensive skills (think of transmuter skills or assassin's martial trance) - and let us go on about our business. Gear or preps that require intense area knowledge should really amount to 10% capability change or convenience - not 300%+ boost to effective hit points.

I know it's a touchy subject given how much effort there's been in keeping this system going for 15+ years or so but we're making this more complicated than it need be.