Okay, that's good enough advice for me to stop doing that. You're right, just because the asset was made by someone else doesn't mean we can't make it ours (not stealing it, changing its look XD) and that we're cheating.

I've had someone asked me to create something for them in 3d before, and yeah, the deadline was short, 2 days, but good thing it was a logo so I could finished it (made a couple iterations for the client to choose) in 1 day. If it was a character, then I don't know how to finish it--let alone making a couple iterations in 1 day XD
Ok, I think now I'll start to use some pre-made asset (only) when needed.