I'm hobbyist not a pro but, I have settled on a few recipes I use for different purposes. I played a little with exotic oils, goat milk powder, etc. I have to be honest. This is just my opinion but, unless it's a very special purpose soap, I don't feel the slight change you get from the exotic ingredients is worth the cost. I do use some exotic oils in my charcoal face soap but, that's a special purpose soap. If I was selling it, they might make sense from a marketing standpoint. The only ingredients I use in most of my soaps that I can't get at the grocery store are castor oil and soy wax and those are relatively cheap.
I always use a
lye calculator on a new recipe no matter how I come up with it. I keep recipes in a spreadsheet with notes about what I'd like to tweak next time till I get them where I want them. Once I get there, that's the recipe I use for soap for that purpose. Any changes to the oil weights or lye (sometimes I use mixture of KOH and NOH) go through a
lye calculator.