Any price range... how can you tell if a scope is reliable in that the zero does not wander, that it is not adding in some other variable to throw shots and drift? How important is crispness all the way to the edge when only the central 25% is actually used in the act of aiming?

I know the more expensive scopes have better optical clarity and so-called 'light gathering' but how important is this in just aligning the sights with the point of impact?

How does one 'judge' a scope?

The advice I have seen is vague, mostly along the lines of 'try a bunch of them out'... and reviews even say that very expensive scopes are not all that good. I understand how to assess a rifle or pistol but have no real idea with scopes.

Consequently I have relied on old Japanese Tasco 2-7x32 AO scopes that I know are good because they were used by many FT shooters in the 90s. They seem good quality, but they are old tech now... or are they?