Brooks saddles have been around a long, long time and have endured all sorts of abuse. Some swear by leaving it alone and letting it break in and age on its own. Others actually soak it in motor oil and bake it in an oven before its first use. There are also those who say you need to beat the crap out of it with a rubber mallet.
I have only heard of one person who actually damaged their Brooks to the point of not getting a decade of use out of it.
I use Fiebing's Aussie Leather Conditioner only because I like the smell of it better than Proofhide.