it is a window that starts with usage and continues for five hours.

When I was doing an evaluation using a lower paid tier of Claude, I would have a service send a "hello" ping 4 hours before I started my work day, to reduce my first work-hours session window to 1 hour.

The goal was to have this be more of a "thinking" session for planning the next larger block of work, and then being able to use a lower cost model for implementation.

That said, if your 5 hour window quota is 15% of your weekly quota, this means you can be using 30% or more a day of the weekly quota.