Do I have to return my rental the moment my car is done at the shop?

My car is in the shop and insurance is covering my rental. It's supposed to be done by the end of the week, but my rental is booked through the 16th. I have some very busy days coming up and lots of driving to do- if my car is finished on Friday it will be pretty tricky for me to manage to collect it until Monday or Tuesday. This is within the rental period, but I imagine the shop communicates to insurance when they finish the repairs, and at that point insurance expects me to be back in my own car and not the rental? Once it's booked through a certain date, am I good to keep it until that date (or at least not return it like a full week early) or is it different with insurance rentals? Not trying to exploit the system, just not sure what's expected of me. Cheers