As some have made similar posts already just adding my 2 cents .. Ive been an occasional visitor here in the past , I am a regular on several other boards.. but ..
Take it from someone that has always bought old boats .. and learn from my mistakes and experience..
I bought a boat not me first , but was first used glass boat back about 8 yrs ago .. boat had issues , but motor was good, and it was dirt cheap.. later found out that all the wood in boat was rotted except one small area in the front .. and the decks where good, but beyond that was rot.
I had know idea the cost of replacing the transom .. I got a few prices.. transom alone was 800 -1200 on a 15ft 1977 Bass Boat!
That didnt include the floor, and stringers.. I was like no way .
Surely I can do my self.. after much searching net .. and a few months went by .. I gathered all the info I needed to dive into the project.. and replaced all the wood and glass .. that first boat took 4 - 5 months
Ive done 6 more since then .. working on the most current one now a 1987 Hydra-Sport 17 ft . But I knew it had issues with rot.. but some rot say transom, means lots more rot...
If you buy used check engine very closely.. best take it to a shop and have the engine closely inspected tell them your looking at buying ... do compression and leak down test, check condition of lower unit oil, signs of water, grit or metal in oil, etc
If you buy a 2000 and before unless you get very lucky expect some rot, 99.9 percent of boat before 2000 where made with wood, and also easier to fix when issues arise .. new boats if stringer breaks, or de-laminates.. the way the new boats are made you are pretty much screwed.. unless your the first owner , 2nd owner lifetime warranty is not life time for most makers.. its about 3-7 yrs.
Main thing is to educate your self on all the ins and outs of new and used .. and know if you buy used expect the worst pray for the best ;D