If you have an agreed meet time with a provider, and you text her when you arrive, and she (or her handler) tells you to wait cause she’s not ready, how long would you wait past the agreed time ?  10, 20, 30 minutes ?  I’ll start by saying 30 minutes is too much.  

and I don't have any time constraints myself (something that I always try to arrange), then I might give them up to an hour, depending on how much I want to see the person.

 
On the other hand, if they just ghost you, even after you try calling and/texting, then 30 minutes is the max.

I would not make anyone wait. I like to be on time if not a few minutes early. She obviously was totally unprepared & that’s ridiculous. If I booked any appointment never again would I repeat, or wait 30 minutes.

I do my own nails because my last nail tech did that’s bs, and I spend my money where it is appreciated. Repeat business is the best. Pick a pro.

I agree, being late is not ok.  
In any business.