astigmatism and wearing glasses in young child

[tomhazard]

I've just been to the opticians with DS age just over 3. I suspected a squint but it turns out that his eye is becoming lazy due to a pretty bad astigmatism in his left eye, and a more mild one in the right. He is also short sighted. The optician would like to do more tests in a few weeks with eye drops of some sort to make a more accurate diagnosis and then very likely issue DS with glasses.
Now, my main worry here is 2 things:

1. will this astigmatism likely get worse or do they stay the same? Will it have any effect on his life other than wearing glasses?

2. how the heck do you get a 3 year old to wear glasses?! Do you have to buy a zillion pairs because of loss and breakage common to this age group?

DH and I are both short sighted but didn't come on until our teens, and neither of us have astigmatism so it's a bit new for us. Thanks for any experiences.

Orthoptists deal with eye issues in children. My dd was under orthoptist care until around the age of 8 at which point we moved to a local optician

The reason I ask is that there is a link between higher end astigmatism and other eye issues like squints and nystagmus and I've only ever heard of orthoptics being seen in relation to those. Do all children see orthoptics then?

I think they see him to see how his vision has changed with the glasses. I think he will do the same test he failed but wearing his glasses to see if his vision has improved with them. I imagine they monitor for squints etc too? I think it’s standard practice. They didn’t say he had a squint or anything...