Replying to Reviving an old jacket

i've been through a few more modern jackets recently, a rab and a couple arc'teryx ones, but their durability and look when worn just puts me off buying another new jacket. I have actually gone back to skiing my dad's old north face gear from the 90s and that shit is not only insanely durable, but looks even better when repaired. Aside from weight whilst touring, the only issue with the old gear is that the waterproofing isn't quite what it used to be, I've been looking at Nikwax but I also think that I may need to fix the seams as well. Would appreciate some advice on taking care of old gear, and i like the sustainability aspect of not buying gear that will be out of fashion and deteriorating within a couple years