Wash when you change girlfriends.
I wash them every week. I’m single and sleep on
a floor mat.
In addition to washing them every week…DON"T use fabric softener on them…basically it’s not a good idea to use fabric softener (liquid or sheet) on fabric that is designed to absorb sweat (or water) like underwear…towels and sheets…
Fabric softener puts a waxy film on the fabric, which kind of defeats the absorbing feature…
We use white vinegar…it’s cheap and because it’s acidic, it cleans up soap residue…
dave
When I was single and childless, I changed the sheets whenever I had a date – just in case 
. That meant every week or two. Now, I wash my sheets every week – I have sex on them once or twice a day and it just seems nasty to go longer… I also wash the kids sheets once a week – all three beds on the same day. It’s just easier and more practical to do them all at once. The exception is when my husband is out to sea – then I very often skip a week. Of course, when my old man is gone, I’m more slatternly in general and tend to skimp on the housework as a whole.
I’m definitely of the once a week crowd, on general cleanliness purposes. I suppose if we all bathed before bed I might let them go longer, but there’s still the drool factor. I have let them go for 2 weeks, and I can really tell the difference.
In any case, there is nothing better than the feeling of slipping between crisp, clean sheets. I read in some magazine article about Oprah once that she has her sheets changed every 3 days. I was immediately struck with intense jealousy at this luxury.
Did I read this correctly? Some of you actually wait MONTHS between washings? Sorry, but thought of that makes me shudder. I’ll bring a sleeping bag next time I come to visit.
The sensual pleasure associated with slipping into bed with my SO, between clean, crisp sheets cannot be overemphasized.
All bed linens are changed a minimum of once a week in my house.
I dunno what you mean by “floor mat,” but when I read that I imagined you in a fetal position trying to sleep on the floor mat from my old Toyota.
After reading you people describe how nice clean sheets feel, I decided go ahead and wash my bedsheets. Unfortunately when I tried to bend them to put them in the washer, they broke. Should I have used fabric softner or something?
I tend to shower before going to bed, and therefore I feel I can let my sheets go for a couple of months or so. All that oil and dead skin has just been sloughed off in the shower. Sex changes that, but since I have a twin bed on a loft (for convenience) and my SO has a queen size bed at a normal height… it’s usually her sheets that need to be changed 
Weekly.