A good way that works for me is dumping on a piece of paper what are you open point at the moment you are left, could not be the best (or only way) to handle it but it's fine .
Eg. Yesterday i've been working on a web form
Before to leave:
- Check if Button x behave as described by req.1
- Add javascript alert on button y click
- Verify that procedure x works for a given impunt
Hope this helps
I don't turn off my computers. I use Xmonad and have tasks running on different 'desktops' which I leave open for days/weeks. In terms of code, I leave the Emacs sessions running with buffers, repls, etc. open until I logout or reboot.