I wouldn't swear on a Bible, but I'm pretty sure in 33 yrs of shooting, started when 10, I've only had 2 centerfire rifles lose zero, and both were when the Tasco World Class 3-9's came unglued!
I don't baby them, but careful not to go knocking them into things scope first and since the Tasco's have bought Leupold, Bausch and Lomb (sp?) and SWFA chicken scope.
Mike