I have it in my terms and conditions now so that there is no mistake that I have allowed for all closures and my price is a 12 month price. I had one problem 2 years ago but have not had any problems since. One thing I would like to warn about though, even if you are doing the cleaning you should charge and work the same as if you have someone in otherwise a client will complain about a change in serviec when you put someone in. I am talking about an owner/operator will have a tendency to work extra time if they think the place needs a little extra attention but if you put someone in they will leave as soon as they get a chance if not before. If you do not charge for Christmas and New years when you are in there the client will complain when you get someone in and now charge them. Always try to keep a consistant approach regardless of who is doing the work, it will make it easier when you put someone in. It is hard when you are doing the cleaning, I must admit, you see something wrong you just want to clean it.
Gilbert