I've just had the pleasure of taking over a very good violin pupil the other day. She is 13 years old, very bright and in to tech.
I try to get pupils to record their practice and email it to me once a week so I can have a look at what they are up to. It’s not really a check-up but a way of helping them to keep a “playing journal”.
Using their phones they will have to send me a small clip of a scale, a bowing exercise, a phrase or a complete performance. Having spoken to my pupils, (most of them) like the fact that I’m interested to see that they are working during the week and that I take the time to reply – just a short sentence with a pointer or two. It’s not too time-consuming.