I was looking at several sailboats and started wondering how old is really too old to offset the price of fixing it up??? There are alot of people getting rid of their sailboats including giving them to charities.... I guess my question from more experienced sailors is when does a sailboat start to cost more to fixup than buy????
This a hard question to be truthful.
Many factors are involved. I like to play with boats and I also like to experiment.
My woman ask a few months ago a question similar to yours; "When is the boat too old to be cost effective to fix?"
I have not ever met a boat I not like, though I have met a few uglier than others.

But, we all pretty in our on way when people care enugh to look inside.
I try to keep my posts short, but, also, people sometimes not understand as I not go into deep detail.
Here the list of buying a $4,000 USD boat (plain jane) and fixing her up into a world class cruiser! :laugher
This was a list I made over one year ago to show my woman how things can add up depending on what we want.
Sure, we can buy with many of these things already on the boat, but, IMHO, cost go up, what is installed is used and I talking new "OR" self made (another thing I enjoy to make stories longer) :laugher ! But, I never met a boat I not like or ......... was too old. It depends if it a hobby and fun to spend my time and money, etc.
Boat $4,000
Radar $2,000
Brass Bell $ 50
VHF Radio $ 150
Wood Stove $ 450
Air $ 500 This fans, A/C, backup heat, etc.
2 Anchors $ 150 Bruce & Delta Plow (Delta Fastset $122, Manson Supreme $240) 22 lbs.??
Sea Anchor $ 300 Parachute (Para-Tech 25' boat Dia.9')(Fiorentino 30' boat @10,000 lbs. Dia.6' @$457.00)
Chain $ 200 ??50' of 1/4" G-4 High Test??
Ropes $ 300 **Various Sizes**
Rigging $ 500 **Various sizes and hardware**
Rigging Tools $ 300 %Crimping and Cutting%
Compass $ 100
Fenders $ 105 4 @ Commercial 6"x25"
Barometer $ 100 Weems & Plath?? or other
Canvas $ 300 Approx. $3 per square foot 9.5 oz. w/grommets
Sewing Kit $ 50 **Estimate** sail repair, needles, twine etc.
Cleats $ 100 Extras Various Stainless Steel
Boat Hook $ 35 Adjustable 54" to 12'
AGM Battery $ 400 This vary, try for 2 batteries limited to the $400
Battery Monitor $ 50 This may need to be home made
Oars $ 150 Home made, 2 rowing and one Sculling. This include Oar Locks
Solar $ 300 Shop around
Generator $ 300 BlueWind w/voltage regulator
Wind Vane $ 150 Tiller Steering. Possiable home made, may cost more to buy
Zincs $ 50 This depends, may not need
Deck Prisms $ 40 2 @ large. Be cheaper for small 2 @ $20
Kerosene Lights $ 300 Vermont Lanterns (Anchor, Masthead, Port/Starboard)
Sextant $ 575 Astra III B Deluxe Can buy a nice Plastic Davis for $170-240
Plumbing $ 300 This depend on what needed. Think; head, shower, tanks. **Sewage Treatment $1,000?
Water Maker $2,000 Katadyn Manual Water Maker
Fire Ex. $ 100 This 2 plus extras that may be needed.
Safety Flares $ 50 Depends on what used
Tethers & Vests $ 500 This extras for guests. Lines, vests, tethers, netting etc.
Hardware $ 500 Optionals; Blocks, wind direction, etc. Just whatever as little add-ons.
Total $16,305
Vinyl Graphics; Graphics $200??