I remember seeing an interview with David Blaine where he was asked how he manages to achieve his incredible feats, how he persuades his body to endure sixty three hours encased in ice or thirty five hours atop a pillar.

So your teenager takes themselves off, unprompted, to revise on their own? Firstly, don’t brag! Secondly, don’t think your involvement is not needed or unwelcome (no matter what they say, shout, throw at the door...!).