It depends on what I'm drawing, and it depends on what medium.
Any Painting I do takes at least 1 hour right off the bat, I've never finished a painting and been satisfied with it in less than an hour no matter the size. (Even 2 in. by 2 in. dollhouse paintings leave me tweaking them), and can clock upwards of currently 9 hours. Though I will definitely spend more than 9 hours on paintings in the future.
Any digital drawing takes about an hour right off the bat as well. Mainly because I have a shaky hand and digital art is actually one of the most difficult mediums for me, due to this. It doesn't help that I used a trackpad because my tablet doesn't have a pen and my mouse broke The longest I've ever spent on a digital drawing so far is probably about 2 or 3 hours, though that was when I was just figuring out GIMP and such, now it's more like 1-2 hours.
Any drawing, pen or pencil, that I've done is usually done within an hour. Including every pen and paper thing I've drawn so far (Granted I don't have many good ones posted currently) I think the longest I've ever spent on a drawing was maybe an hour and a half, and it was drawing 40+ characters in a school setting a few years back. Sketches literally take me minutes, and concepts take me maybe 10 minutes. coloring is probably the longest process honestly.
Admittedly, every single thing on my DeviantArt currently took less than an hour to make, except for one of the Paintings (The textured one) because I was continually unsatisfied with it. I guess I oughtta start posting more quality stuff, nice poll!
hahahahahaha finish a picture!?!?!XD I've only done that once -_- ....the ones i post is just me saying "i hate this, it looks horrible... but im sick of it... so ill just post it and never have to work on it again"
Depends on the picture. A large picture, such as a Transformer, takes a butt load of time and effort because of the detail. For individual people/poses it usually takes me a couple of hours to finish, but I rarely work straight through. I work on my art off and on throughout the day, and I'm always editing or adding to a picture.