I think it depends on the amount of piggies and cages you have. You'll have about two loads of washing each week, as fleece and towels are supposed to be changed every three to four days
And fleece is almost instantly dry when it comes out the machine, without being tumble dried.
The fleece you would be looking for is called anti pill fleece, or invest in a slightly more expensive anti pill micro fleece. These can be found in stores like Primark, eBay, the range, bargain stores, asda and other supermarkets.
Fleece needs to be changed every three to four days, without a fabric softener, but with non bio detergent and white vinegar(optional) at 60 degrees. Before first use you have to wash the fleece without any detergent at least three times to allow it to remove the water barrier. You can check this has been done successfully if a drop of water on the fleece sinks through, not stays on the top. If it stays, you need to wash it again.
Fleece also needs an absorbent layer underneath to hold the urine. This can be towels, which I find great. Or puppy pads. You can also buy cage liners which are fleece, but built in absorbent layer. You can buy these from:
MyGuineaPigPals (on the forum)
My Guinea Pig Pals
CandECosies (on the forum)
CandE Cosies - Small Animal Accessories
http://ziggyspiggies.webs.com
Fleece needs to be spot cleaned (remove poop) at least once a day.
To avoid clogging up washing machine you will need to brush down the fleece and shake it to remove loose hay and hairs. And optional would be to have a horse wash bag, found on amazon/ebay which allows fleece to be washed well, but all hay and hairs keep contained in the bag.
I hope I've covered everything? Hehe