Should you buy used shoes?

Only if you live in nyc.

I've bought 2 pair of used shoes in the past year. Has worked out well but in my case, it's a model of shoe I've worn for a long time and there were very good pictures of the soles that I could compare to my own worn soles. I could compare all the little grooves and such or lack thereof to determine that the "new" used shoes would be like new to me. $30-$35 compared to $70-$90 gave this old geezer quite a thrill. I wouldn't try it with a model with which I was unfamiliar.

Depends who wore them

I wouldn't recommend it. Think about it, when you break in a shoe, it's adjusting and conforming to you. If it's already been worn by someone else, it won't be the best for you, which is something a running shoe should be. Unless someone has exactly the same height, weight, speed, pronation, foot strike, transition, etc. as you then it's not a good idea.

I wouldn’t recommend it unless you knew that the person wore them 2 times and they didn’t fit. Otherwise, why buy a shoe that the previous runner thinks is past its useful life?