There are so many variables, each case is going to be different. I bought a 24' Venture new in 1971 for $4500, kept it for 5 years and sold it for $5000.
I bought a 28' Kells new in 1976 for about $17,000, sold it 22 years later for $7500 (it needed some interior work, not rebuild, but replace some deterioated wood). Finally, I now own a 2000 Catalina 320, purchased new at $80,000 and from the resale lists, it would bring $65,000 - $75,000 today (It's in like new condition and I plan to keep it for a long time). A new 2009 model with same equipment would be about $140,000 (I guess). A lot depends on how you take care of it in those 10 yrs. and whether it is a popular design that will hold it's value.