How old is your comic?
I have two (technically three) comics running.
The J-Man passed 2 years online on August 26th (BTW guest art is still open)
The Valve is around 1 1/2 years old, starting on March 16th, 2015.
Tales from the Other Side, where I post other comics I make, is a year old.
Have you ever started and then abandoned a comic before moving on to a new one?
Not yet, but I almost did. For the first TftOS I started redrawing J-Man 1933, a comic I made for Sophomore year at SVA. It wasn't more then a year old when I originally drew it, but I made it with traditional inking (which I'm not good at) and questionable anatomy. So I redrew it digitally, which I thought wouldn't take long.
But then Junior year started and my Thesis basically took over my entire schedule. Trying to do four comics at once was too much and my upload schedule took a big dive. I was at the point where I thought about abandoning J-Mam 1933 halfway through. Eventually I did finish it a year later. My thesis, Cinderella, now uploads on TftOS, and since that's already finished, I don't need to worry about it messing with my other projects.
How long did you expect this project to last when you started it. How long do you expect it to last now?
Not really sure. As long as I can make them, I guess. J-Man and Valve are ongoing and I have plans for at least 12 chapters and more. Tales from the Other Side is an anthology with each chapter a different story. I don't really have a plan for that one so I don't know how long it'll last.
Do you have an ending planned?
I have ideas for endings for both J-Man and Valve, but they won't come for a long time. I'm more familiar with western comics that go on then graphic novels that have a planned ending, so I've been making my comics like that. My comics don't have a planned ending as of late, but If I do get to do this for years, maybe I'll end it properly.
Thanks for the questions! I've never thought too much about length or endings, so this was a fun exercise.