Hunted with a slug gun long enough to realize its effective distance limitation. Even with today's snazzy sabots, 150yds is a long shot to pull off. And, 200yds is really stretchin' it...
Given that mediocre distance, ya really don't need lots of magnification to shoot a big bodied animal like a deer. 10x max should be plenty, and ya could prolly get by just fine, with half that much to engage an 8-10" vital zone...
To expand upon post, above...
What your aging eyes really want are two things:
1. Clarity
2. Brightness
#1 is covered easily by purchasing quality glass, with quality coatings
#2 is assured by the scope having an adequate 'exit pupil' value. Simply stated, the larger the exit pupil a scope allows, the more light is 'transmitted' to your eye. Subsequently, the image thru the scope is brighter...which is what lots of deer hunters appreciate in those waning minutes of shooting light...
Exit pupil is easy to solve for, just divide the scope's objective diameter by the magnification power. So, a 2-10x50 scope will have a huge 25mm exit pupil on lowest (2x) power, but decreases to 5mm exit pupil on max power. (50 / 10 = 5) See the easy math?
According to most things I've read, 5-7mm is about the most the pupil of a human eye can open, so anything beyond that value is 'extra'. So, if your scope allows that, you're getting about all ya can outta that scope/mag setting. Whereas, if the exit pupil of a scope falls much below 5mm, then the scope image will appear darker than ideal...
So, ya basically want to pick a scope that'll allow at least a 5mm exit pupil at a magnification setting that you're comfortable shooting at. Do some quick math, and you'll see that going UP in max mag isn't always the best answer for hunting with 'aging' eyes. Give your tired eyes what they need...more LIGHT! When choosing a scope, remember how objective diameter factors into the 'easy math' for exit pupil. The bigger the objective, the better...as it relates to magnification...
Oh yeah, a lit reticle is a nice touch, if the reticle is too thin and/ or lacking in contrast. I just put a Minox 2.5-10x50 back on the smoke pole for deer season. It allows the same 'ideal' exit pupil @ max mag, so it's very useable & bright thru the entire range. And, the center part of the duplex reticle is lit, too...