Generally, there are two types of boat surveys, Insurance and Purchase. Insurance is the one that says "the boat will neither burn on land nor sink in water, or it won't if you get these problems fixed or brought up to current code". Purchase surveys look at the whole package and provide a basis on which to negotiate price breaks or compromises. Generally, insurers don't care about dirty hulls and crusty halyards!
I found that insuring my 35 year old boat as a rider on my house insurance was $600/year, while going with a "yacht insurer" dropped it to less than $400, and it hasn't budged a penny in seven years. I have issued the firm insurance surveys every five or six seasons, along with annotations indicating where I had made improvements or fixed old problems.
Note that customarily, it is things like your Zodiac or outboard that gets stolen, or your gear should the boat be robbed. Total loss of the boat is relatively rare, and I would say more boats are destroyed in winter layup via yard fires or hurricanes than at sea...so take your stuff off the boat.
I have power tools on board mine right now, but that's not usually the case. Most of my electronics are at home.