I think it really depends on the individual. As someone who takes strictly AP/Honors classes, works, and has a lot to do at home, sometimes stuff gets done on my end in like a few hours or a few weeks. Because I'm either busy busy busy or like "ayy let's just sleep for the next 7 hours instead of acknowledging responsibilities".
I mean straight up conning is one thing though, definitely. I try to avoid that as much as possible myself, cause like I said, sometimes it takes me a while. Example being, on my commissions I require half payment up front. If it takes me 2 months or more, I repay the person price and a half - so if the overall commission would be, on dA for instance, 50 points, they'd get 75 from me.
Art trades are trickier as there's obviously no set price so I usually just go above and beyond on what I was originally supposed to give in my part of the trade.
Not everyone has those sort of policies though, which doesn't really make it possible to strictly call people out on their con if that's what the case ends up being. Really though, I don't run into that too often - more often than not, people just get really busy or their muse dies and they forget they've been commissioned.
