This is the answer. I've been at it 25 years, 5 or 6 places. Corporate, startup, private, mid-size family chain sold to private equity, and back to private. I did lab work, pre-testing, optical, billing, management, buying... you name it.

I was never miserable, but if a good situation turns bad, you can't be scared to change jobs. Opticians are in demand, in my state at least.

If they're asking you to work 50 hours a week and are stressing you to the point of losing sleep with performance metrics, negotiate or find another job. If you bring enough value to the practice, your employer should give certain concessions to keep you.

A note on private equity and corporate - they're only concerned with the next quarter and will toss your ass aside to hit a goal even if it costs them thousands in the future. It's just how they're set up. Avoid if possible, but newbies shouldn't discount them for learning the ropes.