Brooks saddle cracking. I apply the proofhide that comes with it religiously, when I first got it about once a month, had it about 5 years or so and started applying more
How to "Proofide" Your New Brooks Leather Saddle - YouTube
Brooks Proofide Saddle Dressing 25g - BikePartners Bike Shop
Brooks Proofide Jar - 50ml Singles | Tree Fort Bikes