Our mechanics sub-group meets almost every day during the build season. During the workweek we only meet for three or so hours to discuss strategy and design, and to order parts. We almost never build anything during these days. This allows the students to focus on homework and school.
Friday and Saturday are the days when we actually build things. We work until the parts are finished. If they're done at 7:00 that’s a good thing
If they're done at 1:00... that just sucks. We figure that no one is actually going to be doing homework on these days anyways, so robotics won't interfere with school.
We also work on Sunday, but only until 4:00 so people can finish their homework.