What is your requirement for furnace size? It has to be properly
sized. Over or undersized furnace is not a good thing.

The current 80% Bryant is 90,000 BTU/H input. I'm going to presume that's
the right size unless someone tells me otherwise. Obviously, it could
absolutely be wrong all these years but I've never noticed it not keeping
up on the coldest days nor during normally cold winter days does it have
extremely short cycles. Lennox guy did walk around and see the place,
count vents, and so forth but never said oh, you should be at 70K so I'm
guessing that was a write-o. I didn't notice it until after he'd left. If
I do talk to him again that will be the first question.

Carrier - Payne guy just went with the 90K but then again I was asking
about replacing what was there. Alas, his paper work doesn't mention model
numbers.

They can't fix it in 24 hours mean lack of needed parts not serious
break down. Furnace is not really complex
electric/electronic/mechanical device.

I've repaired the current unit over the years. Inducer board, gas valve,
inducer motor. But aren't new ones more complex with expensive
microprocessor boards, and trouble codes, especially the HE ones?

Seriously thinking of pulling off those parts on the old one when it goes.
Either to eBay them or just to keep for sentimental value since I put them
in.