I’m not sure if this is technically legal, and it’s certainly not moral, but I kind of don’t give a crap: I just replaced my 48T 1/8" chainring with a 50T 3/32", and slapped a 3/32" chain on it, too. Yeah, I know, it’s called an EighthInch Scrambler for a reason (the old-school 1/8" chain, if you’re not paying attention), but you sometimes have to do what’s necessary.
Or, "Why It’s Important to Take Care of Your Parts"
I bought this Shimano XT cogset back in 2004. It’s lasted me through two chains (about two years each) and now I’ve just begun breaking in a third. I average 2k-3k miles a year, so I’ll just call it 10,000 miles on this one cassette, through dirt, gravel, dust, streams and even a little road riding.
What’s the secret? I clean it regularly and keep the chain well lubed with Pedro’s Ice Wax. That’s about it.