Hairdressers book by chair. Spas book by therapist + room + equipment + duration + prep buffer + recovery buffer. A 60-minute facial doesn’t just need a therapist — it needs the right room, the right machine, the right cleanup time before the next appointment.
Most spa SaaS was built as a salon tool with bolt-ons. The edge cases get painful fast: two therapists who can do the same treatment but only one of them owns the dermaplaning tools, gift voucher recipients who don’t exist in your customer database yet, package balances that need to span treatment categories, hot stone treatments that block the adjacent room because of the smell.
A custom build models all of it correctly. And costs less over three years than the SaaS subscription you were going to keep paying anyway.