For the short time that I have dabbled in astronomy and old scopes, I would be embarrassed to actually tabulate the number of scopes, spotting scopes, and binoculars, that I have been through. I am certain, combining all three, I am well into the triple digits all in the course of a few years.
All that aside, I have bought and sold multiples of C102Fs, C102s, C80s, Firstscope 80s, and C90s (astro and spotting), etc. I will definitely buy another Firstscope or C80 again. Actually, ESPECIALLY, if I find another fluorite scope, I do not know if I could resist. In my limited experience, they are truly amazing. Although, I had one Firstscope 80, it was beat-up and had a 1/3 of the coatings gone, that was stunningly sharp on the moon. It stands out beyond all the others. Weird how that works.
Currently I only have my grandpa's old SPI, a few classic binos, and a current day Kowa (88mm Prominar fluorite) spotting scope. I never bought any of my scopes with the intention of reselling. But, somehow, it always happens. The SPI will not be going anywhere, though. I guess it is a bit of my childhood ADHD peeking its head out.
I WANT that one, but now I WANT that one...oH wAIT!!! I NEEEED that one! 
If I had the room and the money to keep them all, though, I absolutely would. There are many on my list of wanting to at least look through.