Temporary insurance vs. being a named driver
Rather than taking out a temporary policy whenever they want to drive someone’s car, a student could get added as a named driver on someone else’s annual policy. This could be a good option if they drive a lot, but if they’re an infrequent driver it might not be the best bet. Students are often younger, newer drivers - so annual policies can be more expensive than when you’re more experienced. As well as this, it means they can only drive one car, plus the car owner’s own policy and no claims bonus is at risk if something happens.
With temporary cover, however, the student can borrow different cars by taking out ultra-flexible, short term policies on them whenever they need to. They won’t be shelling out while the car is parked up and not in use. Plus, they’ll have their own standalone policy, so the owner’s policy and no claims bonus will be protected - which makes it much easier to find a kind housemate or friend to lend you their car!