At my office-located jobs, I waited to complete 7-8 hours of work (excluding chit-chat, etc) in order to feel satisfied. Now I can do with 4:30 on average. For me being interruption-free is a huge boost.

Personally I do believe in measuring effort in work-hours. Assuming you feel optimal (which I constantly make sure of), the more time you spend the more you get done. Also, 90% of webdev does not require that much creative hard-thinking imo.

My question simply is - do you find 4:30 of work a day acceptable (for you)? And marketable (for employers to accept it)?

Anyway, feel free to post how many hours you work, and what you think about it.