So then a minor dents are common for used items as well ? Because it is virtually impossible to not slightly be hitting tables or chairs while focusing onto your shots and walking around
It is not virtually impossible...just need to have some spatial awareness and be careful.
I see it all the time at league, some people just don't care or have the spatial awareness and bang their cue into the table or chairs all the time. I almost never hit my cue into the table...I would guess maybe 1-2 small taps in the last year, none of which resulted in a ding. More likely to end up hitting the cue of another player at the next table who moved behind me without me knowing. Just doesn't happen to me because I take care around the table and always have awareness of where my cue is in relation to tables and chairs.