Laundry is not a big deal at all at my house (4 people, DH, DS, DD, and me), but I do a load everyday. I start it first thing in the morning, put it in the dryer at nap time, and put it away before I make dinner. Then the washer and dryer are ready for the next day. Total 15 min maybe (1 minute to toss in, 1 to swap, the rest to fold) commitment daily and it's not an issue - its just a routine.
To answer your question - my husband and I each have 1 towel that we use daily for about 4 days to dry off with. My kids also use the same towel - probably 3 days, sometimes 4. They wear the same pair of jammies for several days also before we switch them out (also saves money by not having to buy so many pairs of jammies).
Wash cloths are another issue. We use 1 daily for bathtime. I use it to wash them literally from top to bottom and then, as the water is draining from the tub, I use the used wash cloth to wipe down the tub walls and BAM - I never have to scrub the tub! It's always clean and shiny! Soap is soap as far as I'm concerned, so the bubbles, shampoo and soap that are mixed in with the water from their bath is good enough for me.
Also, I do not sort clothes (unless they are super special or I know they'll bleed) - everything is tossed in together and washed on cold (also saves on energy bills!) With their nicer items, I hang them to dry in the laundry room and skip the dryer which tends to make them pill and fade anyway (also saves on the energy bills!). Everyday play clothes, undies, etc. get washed/dried every day.
Sheets - I have an alternating schedule with these. One Monday, I'll wash our sheets (both sheets and all of our pillow cases fit into the washer at once this way) and the next Mon. I'll wash the kids' sheets (both sets of twin sheets, plus pillow cases all fit into one wash also).
Bras I take on a case by case basis if you know what I mean! lol! You know what you've done in that bra that day (sweat at the gym, mow the lawn, only wore a few hours) and so just go by what you think it needs.
Best of luck to you honey! Oh, and my kids are 3 and 4 and they are responsible for taking off their jammies, hanging them up, getting dressed, and bringing down their dirty clothes from the day before so it's setting in front (or in) the washer when I get down with my mine and DH. They also know to hang up their towel on their hooks in the bathroom. I'm not a drill seargent or anything - I'm just big on routine!
Oh, and there's this article from the Parent Center website recently regarding kids and chores - if yours aren't helping as much as you'd like - check it out and get some ideas. Mine do make their beds, and my 4 year old son is a pro at taking out the garbage (actually, he loves it! He gets to take it into the garage, flip back the lid on the trash bin, and toss the bag in. Then I ohh awww over how strong he is and he just eats it up! Then on trash night, he'll roll the bin out to the curb - he loves this too! My 3 year old does help set the table and everyone puts their dishes in the sink after they're done with them. We don't pay them - which my parent's think is crazy, but we just explain that in our family we all help each other out and this is how he helps our family and we thank him for it. After all, I don't get paid for doing dishes or laundry - right?!) Okay, I'm rambling now, so I'll stop.... :)