I disagree, the cost benefit of replacing cassettes and chains simply because you are worried about chainrings is crazy. Once again it the OPs money but I would bet money that the majority of people on this forum upgrade or replace their bikes well before there is enough wear on chainrings to worry about. Most won’t wear out a chainring on a mountain bike with the mud, grit that comes with mountain biking, let alone a road bike that is kept even relatively clean. You guys can continue to replace chains, cassettes, chainrings etc every 2500 miles at whatever cost but over the course of 4 or 5 years you may save enough to pay for a significant portion of your new bike. Plus if you do wear out you chainrings after 15000 miles, which is unlikely, you can buy a complete crankset for the same price as a cassette. Do what you guys want with your money, buy new chains, cassettes etc but bike shops make money by selling things, not by telling you that you don’t need something.Except the chainrings could still be ok. So now you'll ruin them too.