I am a used boat fan......... for financial reasons.
Obviously, the first owners take the big hits on depreciation in years 1-3.
As the boats get bigger, so do the punch lists of stuff that needs adjustment, tweaking, repairing, etc. If you are the first owner, it can take a year and several trips to your dealer to get the your list of deficiences eliminated or at least down to a livable level. A used boat usually has all this stuff done for you by the first owner.
The level of maintenance on used boats isn't much of a concern if you do adequate due diligence and make some basic assumptions. The replaceables, like sea water impellers, risers, manifolds, canvas, isinglass, bottom paint, etc. will be in a partially used up state. Make a reasonable judjment on the replaceable's condition factor that into your offer. I advise people to discount that stuff as completely aas they can get by with because you will not want to take chances.......if an impeller has 25% useful like remaining, discount it to 100% and replace them since you will not want to take chances on your trip home or even mess with impwellers during you first year of ownership.
Warranty terms should be determined on the boat you are considering......there used to be a magic year for the optimum used boat purchase......for example: catch a nice diesel Sea Ray in its 3rd or 4th year and you would still have the hull structural warranty, some major engine component warranty, some generator warranty, and canvas warranty.......the only real substantitive risk you might incur would be would be in a bunch or compressors, motors, pumps, lights and electronics.
My last thought is to buy the biggest boat you can get your wallet around..........3-4 foot-itis is a real expensive disease if you have to buy at retail and sell or trade at wholesale several times to get to the right boat. Pick the right boat......I don't know about your use or cruising area, bu†I can tell you that with kids on their way to becoming teenagers, you will be a lot happier in a boat with a wide beam and 2 heads. As far as handling is concerned, experience helps a lot, but I find my boat is easier to handle than a lot of models that are considerably smaller.
Look at a lot of boats and the decision gets easier...........besides, shopping is free and fun!