Commission can be good whilst starting out, but I personally don't like it.
The % split is usually quite high. The salon owner has a vested interest in your business. If you aren't earning they aren't getting paid. Which can cause conflict over if you are classed as 'employed' or 'self employed' how many days off you have, if you want to take a half day as you are quiet etc.
If you are in the situation where you can afford a weekly rent, I would opt for that. The owner gets a set rate. Which means, the hours you work, holidays, days off you want to take are not frowned upon & you aren't sat there earning nothing if you don't want to be.
Either way, the owner is only your landlord... When working on commission they sometimes act like your employer but not give you the benefits of min wage, holiday pay, sick leave & so on.
That said, I think you'd need to have at least 6 months rent/ money to live off to be able to focus on getting your business off the ground, without worrying about making your rent.
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