The military has looked at this quite a bit. This is something I used to teach Naval aviators about. In fact, we used a sleep and fatigue modeling software package to predict performance called the Fatigue Avoidance Scheduling Tool (FAST). What was found is that if you severely disrupt sleep for one night, even 3 nights of over sleeping (sleeping 1-2 hours more than normal) was not enough to restore cognitive performance back to baseline. Of course, a mild sleep deficit would have less of an impact, but performance would still be compromised. Plus, the effects are additive. So getting 30 minutes to 1 hour less than you need for 5 nights, then trying to pay it back on the weekend is a formula for poor performance throughout most of the week.
As others have stated, you can't store up sleep ahead of time either. It simply does not work at all.
Newer research has shown that even one night with a sleep deficit produces a measurable increase in insulin resistance, weight gain and inflammation. It is really bad long term.
You really can't oversleep. When the sleep "battery" is fully charged, your body will wake you up. Unless you are waking up naturally, and feeling refreshed and alert when you wake up, you are probably not getting enough. Since I started tracking my sleep about 8 months ago, I have been averaging 9 hours and 11 minutes per night. But I am retired, so I can sleep as much as I want. The average person needs about 8 and those who train need a bit more, so my 9:11 per night is not an outlier.
Most people have the time to address sleep but their lifestyle and habits prevent them from doing so. You really have to count backwards 9 hours from when you need to wake up, and ensure that you are in bed at that time, with the lights on dim, maybe reading a book, with the TV and computer off. You also have to look at caffeine. Caffeine has a long half life and can interfere with sleep quality for up to 6-8 hours.
This is something that is really worth getting under control. I did not really have this dialed in until I was in my 40s.