We can't use bedding, blankets, pillows or stuffies, because they eat them, but I wash their hard toys once a month, in hot water and vinegar, and a little dish soap.
I wash Mia's once a week everything. Her towel, her bed, her toys stuffed and plastic. Think it's a must as much as she is outside and plays with them.
dang, i have backups of all the sheets Lola lays on, and her grub mat. backup duvet cover (in case of wee wee accident when we're at work - rare). i can barely do my own laundry once a week (hah) try once every two weeks I do 5 loads. unless she pees on big bed. then i gotta suck it up and also hit the laundromat to wash the feather pillow top mattress thing.
edit; but i guess if i had a washer/dryer in the apt (first floor of house) i'd do laundry whenever i felt like it. but alas, its in the creepy spider haven basement. and i dont do that at night.
Drako destroys everything before it can be cleaned, and pee on blankets and soft stuff so nothing of that just the floor and a 1000 toys from my kids. Trough everything away all the time