When I'm not deathly ill (as I have been for months, it seems), I do pretty much all the laundry once a week. My boyfriend is a chef, and has maybe a week and a half's worth of uniforms that cannot be worn more than once between washing, as they get REALLY stinky. I sweat kind of a lot, and wear business casual for work, so I have to at least wash my shirts every time, though I can usually make the pants last 4 days or so.
I put a decent amount of time into finding a split laundry basket, so I can sort clothing as I remove it, instead of having to put all the time into it when it needs washing. So we split it into darks/t-shirts/jeans (cold water), and chef/undershirts/undies/socks (hot water). Sheets and towels go into the hot water side, though I usually only remove them on laundry days, so they rarely even make it into the basket. Towels are used until they smell funky, and I am super sensitive to smells like that, so I am the tester. The boyfriend doesn't even notice.
Sweaters, cardigans, and hoodies take the longest to smell like anything but my body spray or that outside smell, so they very rarely get washed. Every couple weeks I will gather my whole collection of bras (10 of the same bra in different colors. I so rarely find ones that fit me) and wash them all together, in a cold/gentle cycle, then hang them by the center piece, over my shower curtain to dry.
The last bit of laundry I do every month or so is ferret bedding. They have handmade fabric mats and hammocks in their giant cage. And they like to poop on them.