Well... parts break wear out without being pushed hard... one minute the machine works and the next it doesn't it's just how things are. I work on lots of different machines, some parts like tracks are easy to see wear and gauge how much is left... gears and clutch packs inside of housings are a different story however same with engines...
Just saying it's best to be prepared for the worst and hopefully you won't experience it.
Yes this is true. My property is fairly flat so no need for a canopy.
You mention in your original post that you want to get a backhoe too. I was in the same situation 6-7 years ago. I bought a backhoe with the idea of using it for a year or so and then selling it. It is so handing to have around, I still have it. I also have the use of a friends JD450G. While it has it's place to be sure. There's not much I can't do with the backhoe instead. You talked about getting both. If it was me, I'd get a backhoe first and see if it didn't fit the bill for all your projects. It might be slower for some things, but hey, your retired.