All conditions. The backcountry is the last place I want to deal with a scope failure, so a few extra ounces to hedge my bets with a scope that will keep working right is a small price to pay, IMO. The SS 3-9x is my preference for that application.
This ^^^
I ran lightweight scopes including fixed 6 Leupolds on my lightweight rifles for years, and refused to use a scope greater than 15oz or so for the same reason. However, I eventually got tired of scopes shifting zero, erratic tracking, and having to shoot more than 10 shots at the time to sight in a rifle.
I finally gave in and tried a heavier scope with proven reputation for mechanically reliability and immediately felt like a dumb@$$ for not switching sooner. The pros of having a mechanically reliable scope that holds zero and tracks well greatly trumps the minor weight penalty. No longer having paranoia everytime I have a slight "bump" on my scope also adds benefit.
Until someone comes out with a lightweight scope that can prove to be as mechanically reliable as a SWFA/Nightforce, I will be running 20oz scope on my hunting rifles.
