How do you treat your hard-to-replace (vintage, expensive/high-end, limited edition, etc.) jackets?

[AeroFan_07]

silicone free waterproof spray

Back when Wilson's Leather shops were still a common site, I used their store-brand spray on jackets.

Maybe this would be worth a try:
https://www.danner.com/waterproofin...AQStWUqcKJZ3ap-KFXvHQF_H7LEALoMszbLbGSYubf3xa