I have a holiday home. We don't rent ours out because the time we would rent it for is the time we want to use it. I think that is one of the cons of holiday houses - that the most demand will be when you want it ie Christmas and other holidays.
We let family and friends use it in exchange for doing something around the house. No-one has ever left it any way other than immaculate although my ILs insist on moving the microwave. We have very little bench space so I put the microwave on top of the fridge because I only use it once in a blue moon. They move it down to use it and then leave it there so I always have to put it back up and always end up jamming a finger. I'm thinking of giving it to the neighbours.

As an investment....... our advice was that we should think of it as an investment in lifestyle. Even if you do rent them they don't bring great returns and capital growth can be patchy (although I suspect that now is a good time to buy because the market in a lot of tourist areas is very flat).