The bottom line is: regardless of what any guide says or what anybody else thinks, you still have to find a buyer who both agrees with that value and who has that much money.
I remember once posing a similar question to my dad. His advice was to pull a number out of my head. A month from now, if you still have it, your price was too high. If you sold it, your price was too low.
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My greatest fear is all of my kids standing around my coffin and talking about "how sensible" dad was.