builders' remorse?

Hi:
I'm doing research for my latest magazine article and I was wondering
if you could help me. I'm collecting information for people who might
be trying to figure out which kit/plans/finished homebuilt to buy. I
suspect everyone who buys an airplane has a set of factors they're
looking for, but once they start flying the airplane, they find out
there are some other things they should have considered.
For instance, one guy I heard about took so long building his airplane
that by the time he'd finished, he had outgrown it. Cabin size didn't
seem so important when he started.
Do you have any tips from your own experience that might help a new
buyer make a better decision? What did you think was important before
you bought the plane that didn't seem so important afterwards? What do
you wish you'd considered before you bought your plane?
Thanks in advance for any help you can give me.
Lynne Wainfan
Long Beach, CA