This site has been submitted before.

http://news.ycombinator.com/item?id=481910

What are other hackers' experiences with having a very strict, rigid schedule vs more open-ended days?

I used to have a really open schedule. I started working in the morning and then kept on going untill I was fed up ( usually somewhere late in the evening). But after a while I suffered more writer's block related problems and finally said to myself "you're not allowed to work beyond 7pm" this put more pressure on me since I had to have stuff finished before that time, resolving most of the blocks and increasing my total output per day. Nowadays it's not as strict anymore, but I do try to keep to regular workdays as much as possible.