There’s totally a science behind it – but, every leather manufacturer will tell you only to use THEIR soap and conditioner. Use what you like. :yes:
I’ve used Lexol, it’s a decent line. It’s not my favorite on the shelf but it’s very usable. I’ve used it to restore some really old / neglected tack, because it works and it’s relatively cheap and tack restoration usually requires a fair bit of product. I’ve gotten some really good results putting almost desiccated tack into a bag with some Lexol and keeping it in that bag for a week.
I’m with Mouse&Bay that one thing that really keeps the longevity of your leather is wiping down with a barely damp cloth every other ride or so. You don’t have to clean it every ride – and you actually shouldn’t, because then the residue build-up collects dirt and such. I think the non-balanced soap only becomes a problem if used all the time.
Of all the saddle soaps/conditioners made with leather pH in mind I think my favorite is the Belharra line from Devoucoux. It is expensive, but it is excellent at giving a very gorgeous patina, and I don’t find my strap goods mold as much when in storage.
Stubben and Passier both have bridle cleaners with appropriate pH as well; I use the Passier Bridle Cleaner for my daily-used tack and it keeps them glossy and new looking.