From my experience, most people are not likely to change their appearance on a regular basis .. I would say once a year or less for most, and even then it might be minor changes not a full make-over.
For hair, I would say that color is probably a more likely change than style for some, especially given that many have old styles that are not yet unlocked for any hairstylist to replicate. If we ever get "party colors" available, then I think coloring will really take off and be something people will change regularly to match their latest outfits.
I don't tend to expect to have repeat business from customers on a regular basis, and instead rely on their word of mouth as referrals to gain additional customers. It is not a "frequent flyer" sort of business, at least not from my experience.
As with all EU professions, skilling takes time and ped. Beauty skilling adds an additional complexity because it is not a solo activity - you must have someone in the chair clicking buttons in order to get skill.
As it stands right now, Akoz and Ido are by far the highest skilled and well known, and there are others of us slowly building up skills to have a decent level of services to offer our customers.
The number of people skilling in beauty seems to be picking up lately, so we may likely see some fluctuation in business as the market becomes more saturated with available beauticians.
I hope that helps, Kimmi. I'd be happy to talk further with you about my experiences in the "business" (though admittedly limited at this point) if you have any questions.
Beta South 2D, Shop No 56, 
Linear Mode
