If it helps anybody I have an Australian Outrider saddle that is over 15 years old now. I have to replace the girth this year for the first time. I only trail ride, nothing real strenuous but it's held up fine. I keep it in the house and condition it regularly. Sitting next to an older Simco saddle and an older textan saddle the leather quality is obviously not the same but it has held up just fine.
Besides I'm of the opinion ...why would you want to tie a half wild bovine to your saddle anyway?