[Routine Help] Is it better to buy things in kits rather than separately?

Beauty Tips For Body Care
I've been using the Paulas Choice skincare pack for a while now, and whilst I've seen EXCELLENT results I was thinking whether I should just buy the best products separately. Is it better to have things that work together or risk some sort of irritation by combining products from other brands?
Girls Blog 2015
Submitted by quimbleyqueef