Mendip,
It is a nightmare being a landlord. I have worked abroad a great deal and in the past took the opportunity to rent out my property,. After the first two stints i quit the rental market for precisely the reason you have stated, that and finding the place in a mess and requiring significant remedy upon my return. It just wasn't worth the bother imo. When i retire it will be the same, i will keep my places and they can remain empty until i return with just some trusted friends to keep an eye on them. The stress doesn't warrant the income.