How man days a week employee should work?

I'm pretty sure we can be 100% effective just for a few hours per day. 8 hours may be too much for some people, wasting this time. I think it's not about days, but hours we spend on work per day.

I think the focus on 4 days is maybe a little overrated: I think the workload should be more dependent on tasks completed, and this translates more to the amount of hours worked rather than days. I might have 4 really intense days with many hours or 5 more relaxed day with less hours per day. Definitely prefer more relaxed days for the most part.

I want to set 4 hrs every day. Working 8 hrs for five days is too overwhelming.

Five working days are common for many employees; however, a new trend of four working days is also becoming popular.