If you just buy classic old-fashioned stuff, then you won't have this problem. I have a pair of old-fashioned leather boots, and when they were worn out after 5 years or so, I just bought exactly the same boots again. Those type of boots have been available for decades, and I really doubt they'll stop making them anytime soon.
For jeans, I've been wearing plain Levis 501 for years, and when they break I just buy another pair. They might be making slight changes, but for the most part it's the same pair of jeans and it's always available in plain styles.
Same for the plain T-shirts I wear. Sure, colors change a bit every year, but I won't have trouble finding a replacement a few years.