I think there's a video of Edward Sexton floating around out there showing a DB suit he's made (for himself I think) and the trousers are not cuffed. I remember noting that and thinking it looked super sharp.
Unless there's something specific about Wonderoud that makes it peculiarly unstable, this is not true. I have several scents that are more than 10 years old (and I've bought vintage scents from the 60's and 70's) and they're all fine. Store them in a dark cabinet or closet and avoid excessive heat and they'll be fine.
I have a vintage automatic Seiko diver that I haven't worn for over a year. I'm glad that watches have no appeal for me, one less thing to spend money on. I truly don't get the appeal of a quartz watch - they work fine but we're surrounded at all times by perfectly accurate time keeping machines, so timekeeping seems like the least of a watch's appeal.