I worked from home for 4 years straight and never gave it more thought than "work when I feel like working or when the situation requires it." Look at that, my method fits in a tweet!
I need some structure on my day otherwise I procrastinate too much.
That means, waking up early, working from x till y, stopping in the middle for a quick lunch – so basically, just like working on an office.
Different people, different tastes.