The domain is not worth much , without a person needing it
I own a 5 letter domain. Established in 2008 and has held content on it every since. And I made the brand + ended up having a car part , which came out later, that uses the name.
However, the value of it is definitely in the eye of the client. A specific client will know what he has plans to do with it and it could be worth $100,000.
But the average person might just be like... I wont even give you $100 for it.
But to me, it's a good purchase to hold on. I'd develop a site out if I were you.