Hello from the US Gulf Coast and welcome aboard the forum!
Eight years ago, I shopped for about a year before buying our 1995 Rosborough 35 Atlantic Trawler. The Rosborough is a very solidly built boat and it was in good shape, but it was a 17 years old boat when we bought it. I did a lot of looking on YachtWorld to narrow down the list and then made four trips to different parts of the US to look at around 20 different boats. I ended up buying a boat that cost significantly less than my maximum budget and I was glad that I did.
Over the next year, I spent over $30,000 (US) on repairs and fix-ups on a boat for which I paid $77,000 (US). I did most of the work and installations myself. I learned that with a 17 year old boat, even though a surveyor may give systems his approval, both mechanical and electronic equipment can be reaching their end-of-life. I had to replace the bow thruster, the windlass, hydraulic steering hoses, the autopilot, the radar, depth sounder, the air conditioning unit, engine heat exchanger, the inverter, the battery charger, 3 Group 8D batteries, and more. I also added quite a few things to the boat like AIS, flat panel TV, sound system, new antennas, new heads, LED lighting, new radios, etc. I also re-wired the "snake pit" behind the 3 electrical panels. After that first expensive year, I have averaged $4,000 to $5,000 (US) per year on equipment repairs, replacements, and upgrades. That doesn't include the cost of haulouts for bottom jobs.
I would like to second the earlier comments about checking for fuel tank problems. They can be very expensive. You also need to watch for water tank problems and holding tank problems. The prior owner of our boat paid $195,000 for the boat 2 years before he sold it to me. After he had owned the boat about a year, he discovered major corrosion problems in both the fuel tanks and the water tanks. His surveyor didn't identify either problem. Both Diesel and water were leaking into the bilge. He had to replace the two Diesel tanks and the two water tanks. To do that, the engine had to be pulled. He had the job done right and installed 5052 H32 aluminum Diesel tanks and 316 stainless steel water tanks. The cost of replacing those 4 tanks was over $25,000 (US). I think the prior owner was surprised and overwhelmed at the cost of maintaining an older boat. He wasn't capable of doing the work himself and the cost of ownership was just too high. I think he decided to sell the boat to cut his loses.
The comment by Andy G, "There are surveyors and there are surveyors, not all are created equal" is right on the money. I've got two surveys on my boat, one done for the prior owner and one done for me, and both surveys missed significant issues. The prior owner's surveyor didn't catch the tank corrosion problems. My surveyor didn't test all of the systems on the boat and missed the fact that the autopilot didn't work. He also missed the fact that the hydraulic hoses for the steering system had pinhole leaks due to abrasion. He also didn't note that one of the holding tanks had a leak at a weld seam. Make sure to spend some time shopping for a good surveyor.
Good luck with your boat shopping.