I have 4 or 5 different projects started, that are not finished. They were never completed for different reasons, but usually loss of interest or other projects were prioritised higher. I still want to complete them though, but lack of time is my killer.
I have sold about 5 projects as well ... Incomlpete/in-progress ... and these were priced to sell. I knew I didn´t want to go back to them, as they were old builds and I would have spent too much time trying to get them up to standard.
Ive only ever started one project, that I was so disgusted with, that I threw it in the bin ... Airfix´s Gustav Vasa ship. Living in Stockholm, Ive seen the real thing several times and really wanted to do something different, but the kit was crappy and would have needed so much time, I took no chances.
But I dont belive its a "bad thing" toi leave a project on-hold. If you are not inspired to do it, or lose interest, the finished result will show. It´s better to wait until you feel the urge to work on it again, IMO.