It is possible, but I don't recommend it as many people tend to have plans on the weekend, so if it's a formal function or such, tries to get their nails done in advance, normally on a weekday. I believe by doing only Saturdays, you would lose quite a lot of a business and in the end, profit as well due to only working one day of the week would mean a limited amount of time and appointments available with having to travel to each location.