Mostly Unlimited
I think you should think five to ten years on canvas and interior cushions. 5-15 years on sails and running rigging. 10-20 years on standing rigging. The diesel should be happily chugging along. There will be component replacements like fresh water pumps (5-10 years), head pumps (2-5 years). Obsolecence will determine the electronics lifespan, and ultimately the boat's too. I would guess that at 30 years, you are looking at a major re-outfitting unless you have updated it continuously. RD