I am getting a new central A/C unit that has seen better days. It's 15+
years old, and it finally died. I was told they have to replace something
above the furnace (the condesor?). While they are here working on my
furnace, should I just get a new furnace too??

I have a Lennox furnace that is still working, but it's 9+ years old.
Manufactured in early1993.

Of course, they are offering me a package deal to also replace the furnace
if I want. Initially I said no, but I have no idea the average life
expectancy of an average furnace. If they only last 12 years (on average),
I hate to have them back out in a year or so.

Looking for advice for anyone that was in my situation.......