The four questions
They take twenty seconds and they separate almost every studio in the country into two groups. None of them are rude, and a tech who does this properly is usually pleased to be asked, because it is expensive and invisible and nobody ever notices.
The one that catches most people out is the file. Watch whether it comes out of a sealed packet or a drawer. A drawer is not automatically bad, because some studios keep individually bagged client kits, but then it should have your name on it.
What we do about the air
Local extraction at every chair, ducted out, not a carbon filter box that recirculates. Acrylic dust and monomer vapour are the occupational hazard of this trade and the person most exposed is the tech, nine hours a day, five days a week. That is who the ventilation is for; you get the benefit incidentally.
If something goes wrong
Redness, warmth, or throbbing around a nail after any service here, call the same day and come in. We will look, we will tell you honestly whether it needs a doctor, and there is no charge for either. A studio that gets defensive about this is the reason people end up at an urgent care with a paronychia.