Git commit style: All changed files at once or one at a time?

I am saving my work at night with a single commit for many files. I wonder if it would be better to commit for each file but this seems like a lot more work.

I have no problem with the way things are now but I plan to put my code on GitHub and I want it to be easy to understand.

I'm wondering what the rest of you who use git are doing. Also if you could kind of spell it out for me. I'm new to Git and I've been using TortoiseGit and gitk in Windows.