I will be the first to admit I have the "new shiney" syndrome in a bad way.
So when I'm painting a figure and I lose interest I slide it back to the back of the painting area. I paint on a 12x12 ceramic floor tile. So it starts like this....
1 Start painting a unit of Figure A.
2 Become bored or disinterested in Figure A,
3 Start painting Figure B, Figure A gets pushed to the back of the tile, I will get back to it, I Swear.
4 Become bored or disinterested in Figure B,
5 Start painting Figure C, Figure B gets pushed to back of tile. Figure A gets pushed off the tile.
6 Rinse repeat.
Here are some shots of my painting table of dead projects