I read this thread daily in hopes it will help me to remember some oft forgotten piece of gear that is more reliable than others... with exception to my Shop Vac which is my most prized possession for both inside and outside the house/basement/garage/shed (spiders/eggs/dead flies...Swooosh gone! dust Bunnies....gone!). But keeping this back on track with gear
I can comfortably say that by sticking with name brands over the years, I have had positive outcomes with lifetime expectancy - Examples are Lowe 12 year old Alpine Countour IV, Dana Astralplane, 20 some year old Whisperlite, 20 some year old Orange Thermarest Any SD, Eureka or Kelty Tent....
I don't expect nylon to have a lifetime great than 20 years, and in that time new styles will come out that are much nicer than others (Anyone remember many tents from the 80's that you had to stake the flies down separately from the tent body instead of clipping them into the tent body as we do now? Great for ventilation, but you always needed a handful of extra stakes and 10 more minutes to setup.)
I tend to retire/replace gear based on what I see that is new or easier to use, more than the gear no longer functioning. Pepsi-can or Pocket rocket for the W-Light (except winter), Ultralight packs for the Contour or the Astralplane (except winter). sylnylon tarps or hammocks for the older tents.
I have noticed one trend with Merrill though - In the early 90's I bought a coupe of pairs of Merrill Heavy Duty off trail Ridgeline boots(Made in Italy) . I beat on one pair with thousands of miles and many peaks and went through them in 4 years. I still have the other pair, which I use sparingly. Having success with them, Over the years I bought several pairs of $100 Merrill Day-hikers over the years and they have all turned out to be crap - poorly made, cheap cement, cheap tearing heel liners and inner fabrics - usually by the end of the first year.