For anyone considering purchasing a second hand lens, I came across
this video, the content of which I broadly agree with and is fairly comprehensive.
I have no connection with the video producer beyond being subscribed to his channel because I had found his previous work helpful.
I would add that you should look through the lens from
both directions, against outdoors through a distant window, or using a torch, as the video advocates.
One thing I find with Nikon gear is they cannot seem to get the hang of sticking rubber grips to cameras or lens barrels, so if the only problem is an ill fitting rubber grip on the zoom ring (e.g. like on my Nikon 70-300mm), I wouldn't worry about it - I know I have looked after my lens and still it is all mis-shapen
- but it works
Cheers,