Gary Kepper wrote:A good philosophy on the subject,
Buy the smallest boat you can tolerate, not the biggest boat you can afford.
H'mmm. I'd put it as "buy/build the smallest boat that is fit for your purpose". I wouldn't want to feel that I was 'tolerating' my boat.
Somewhere between those two limits is the right-sized boat. Another similar saying is "don't be over-boated". All boats are too big when you're cleaning and painting the bottom, and paying for size-related equipment - but on the other hand everyone who has a boat says "if only she were two feet longer, she would be big enough to fit everything in", and all boats are too small when the crew's on bad terms with each other...
Having said all that, I built the biggest boat I could afford, and could go on affording to keep maintained, but I would add the modifier "easily" to "afford". Leave a margin when you're budgeting, don't stretch the budget to its limit.
Another saying to remember is "Boats cost twice as much to build, and take twice as long to build, as the number you first thought of".