It depends is a mighty useful phrase. I had a fixed 20x scope that fit all my needs for years. It proved inadequate in October when we head for Ystone to look for wolves.
So I upgraded and bought a Leupold 15-45x scope which I rarely use above 40 because of distortion and the narrowed field of view.
This past fall we were in the Lamar Valley trying to see wolves over a mile away. I remember some gal telling me "look for his ears." For the record 40x was totally inadequate for seeing a wolf's ears from a mile away. Her 60x Swarovski with better glass was a game changer but I figure it'll be cheaper to look for closer wolves or ones with bigger ears.
"What kind of man would put a known criminal in charge of a major branch of government? Apart from, say, the average voter." - Terry Pratchett