I've come to the conclusion that holidays are what sposies are for. Seriously. We've just come back from a week in Cornwall, I did take some fluff, rinsed and brought home to wash but we mostly put DS in sposies. A wash and dry in the launderette where we were staying was a fiver - and that was a 'special offer'! I did one load of laundry, clothes, and the dryer time we paid for with that fiver wasn't even enough to get the clothes dry and we had to finish them on the airer out of the caravan window!
Sposies, and not a minute's guilt, for me anyway!