I also used to think you only should carry one complete line....but you do have to learn through trial and error what you like and what you don't like. The best thing is to try whatever it is you use on yourself. You'll be the best critic because you're the professional!! I like Tammy Taylor sanitizers, and disinfectants, and her cuticle oils. But I like Seche for their Top, and Base coat. They make my clients polish last a loooong time!! I also like sticky base coats like Orly's Bonder, and Creative's Sticky. For basic pedicure, I like Gena products. And for my spa pedicures, I use Creative stuff. I alsi found a great company that makes chocolate products. So I have chocolate mani/pedi's. For Polish, Americans looove and demand OPI and Essie. We once had Creative, and Zoya polishes, but they just sat there. Cuccio has an excellent milk and honey system, and I have that. I think it's great to have a tasty menu of services. For enhancements....I use Backscratchers for wraps (the best), Tammy Taylor for acrylic (but I'm training for Creative), and I want to use either Star Nail or IBD for gels. For strengtheners, I've used Qtica, Nailtiques, Nail Tek, and Nail Envy. Different strengthers work for different people. Once again, Trial and Error. Good Luck.
Diya