Yes Jon, I do change the ELT batteries by the date required. I have 5 ELT's since I have 5 airplanes ( well 2 belong to my kids but I seem to maintain them...). But that is a federal law. It was originally based on the idea that the batteries should be changed when the expected output was 80% of new. Newer ELT's use better batteries ( plain Duracells) that require changing only every 6 years or so instead of 2 years on the old ones. And if you cut up a current "Old" style ELT battery, you will find 6 modern Duracell AA potted together in a package, that's all. Those potted units require 2 year replacements, the ones that use the Duracells loose can go 6 years. I wonder if the ELT battery companies really want to extend the useful life?

I wonder if the tire companies really want to extend the useful life of tires, or if they would rather just sell more and more tires to those gullible enough to pay for them? Of course they would rather have the sales and the reduced liability.

Changing tires at some arbitrary date is just a sales job gone overboard. When this business of motorhome tire replacements first got going it was 5-7 years. Now it is just 5 years. Maybe soon we should do it annually?