Both my sons do piano, one started at 4 (he’s 8 now) the other at 10 (he had other hobbies but realised he was quite good at doing his brother’s piano work so he started it too).
Our piano teacher would have them practice the sheet music from that week. My rule was 10 mins practice a day. They could either sit at piano and just play around or practice their song. The point was to actually be at the piano.
I would sit in on their weekly lessons because I enjoyed listening to them. I’d have my phone out and be catching up on things but I had an ear on what was going on.
As other posters have said, kids do not want to practice at home, they see it as a chore but I’m firm with my 10 mins and it’s now part of the day.
I don’t get the comment on piano teachers being a weird breed, our teacher is SO lovely, she’s brilliant with kids, so patient and sweet, I really like her.
I do find that when piano starts getting a little hard, kids will want to quit. It won’t be as fun anymore and they will want to give it up but the hard work is worth it. My younger DS struggled last year as the piano exam was a lot harder than year before but he got there and did well on his exam. We took a break the next term from exam work and just did ‘cool’ songs that he liked, like Imagine Dragons, Beatles etc.
I would recommend getting a beginner piano book for children so you can sit down with your child and both learn about music. It will help if you know little things like the location of middle C, hand position, note lengths…
I play music so I can help the boys but if I didn’t it would be hard to keep them on track if they are playing something incorrectly and I didn’t know how it was to go.