I read somewhere a fairly fool-proof way of dealing with this...throw your scales out, find a pay and weigh scale in a shop and once a week, weigh yourself in as near as possible the same condition that you were weighed in, the previous week.This way, you know the scales are in the same spot, and because of having to pay, say 20p everytime you weigh, you will soon find yourself only weighing once a week!!!
I think this could be a good plan, for I am one of those that jumps on the scale two or three times a day, if I am not happy with the first result!!! But, as yet I have not been strong enough to carry this out....one day....one day!

and it is amazing just how much weight you can gain and lose over the course of a week on a daily basis. 

Great Job Leigh 