I agree with all that's said. Will's suggestion to check zero often is an invaluable one. I agree completely.
I've lost zero twice. Once my .375 with a Redfield scope lost zero and once my mount got lose. Both times were out of country. A close friend had a 1.5 x 5 Leupold break (at the range) and I've seen someone inexperianced with one of the old Nightforce scopes inadverdantly crank on the elevation as opposed to the rheostadt for the reticle. No shooting with that scope until we rezeroed.
The best solution is two scopes. Both zero'd for your rifle/ammo. (you did know that different rounds shoot different places?) I use the Lepold QR mounts for that reason, but it looks like I'll be moving to a different system as Leupold has discontinued the QR series.
One friend always takes two rifles with him when out of country - this is also a good idea.
"I don't make enough money to buy cheap stuff" - Mark Manning