I suppose not seeing the job it could fall in to 2 catorgories, the first it could be a doddle and remain samish each month, or it could be a mare, where you need to scrub or semi strip each month, You could try it for the first couple of months till you get a picture of how its going to be and then put in an extra charge if it gets too messy, think its a suck it and see one si.

Chris