I believe at this time Lennox is as good as Trane...and I own both.

We are past due our two units are 22yo

I was going to get some quotes this month. If I get a modern trane or lennox system do I have any hope of doing basic maint/repairs myself?

I managed to keep ours going the last few years by ordering capacitors, a contactor, and even a new fan motor off of amazon. Super simple inside.

I am afraid a new unit will be like a new fridge made of disposibilium. I guess I don't have any choice. Are there any brands/models that are particularly DIY friendly?

So, is it a package or split system? Are they replacing all ductwork? No joke, those quotes are very high for a unit that size.

I called and mentioned the Ad above. They said it’s a company that sell a the equipment and farms out to lowest installer. I just did that with tiler and it wasn’t good. Anyhow, maybe they Are wrong.