I buy in EXACTLY what the client wants!! Even if the client wants something unusual or something I wouldn't have picked myself I will still buy it, it just makes sense to listen to your customer and providing what they want.
But, it doesn't stop there. That client will return to you because you can and do deliver anything she asks for, so you're securing a regular client which is what we all aim for, a good base of regulars. She also tells all her friends that you can do whatever nails they can dream up no matter how wild or unusual, and when their techs say "sorry no" to their requests they'll start to come to you.
When you look at it like that, the few quid extra on those products is a really valuable investment even if you never use them again. Anyone is welcome for a rummage in my drawers in my salon (ooer mrs :lol: ) and you will see that I have tens, possibly hundreds of foils, glitters, fimo etc. Its all been worthwhile, I market myself as a tech who can offer literally anything, and clients like it, they also like it when they ask what sort of things I can do and I start to show them nail wheels with my vast selection of possibilites, they get quite green eyed and start saying "I'm having that next time, and that the time after...", I have a client who's lined up her next 5 visits with me! So, it keeps your regulars coming back, and hopefully attracts a few other tech's regulars too. Brutal maybe, but thats business.