I've far better things to do with my time than constant washing and ironing. I'm surprised that anyone would boast about wasting their life on doing twice as much of this than necessary
This sort of attitude makes me LOL, especially when the person in question is using her precious life energy to read and post on Mumsnet!
Maybe some of us just move quicker. It takes me about a minute to strip a queen-sized bed & four pillows, about one minute to run the heap downstairs & load the washing machine, one minute to transfer to tumble dryer or line (my laundry room is large with four 18-foot clotheslines) and about five minutes to place on the bed. Less than 15 minutes effort twice a week is worth it to me to have fresh, crisp sheets.
I use a fitted and flat sheet with light blanket, topped by a comforter inside a duvet cover. The duvet cover never touches skin so is washed only about once a month.
It's not about absolute cleanliness - my sheets stay quite clean - it's about the aesthetics of fresh and smooth and crisp vs. several days of wrinkles and creases - and the "feel" of the fabric does change over the course of a few days. Just as some people are content to scrub themselves with basic generic soap and others enjoy luxury products, or some people are content with basic no-frills food and others enjoy special cuisine. Some of us appreciate the aesthetics of fine bedding frequently changed more than others, Same with towels - I've seen people with grubby threadbare rags hanging in their bathroom and they don't even notice or care; I prefer fresh, fluffy towels as part of my routine. There are areas these people probably indulge themselves that wouldn't make sense to me. To each her own.
I don't do wash any more often than I would if I only changed sheets once a week because two sets fit in the washer. And except for the most humid weeks in summer I line dry 95 percent of my clothing, linens and towels. My household is very light-impact and eco-friendly and has been for 30 years so have zero qualms about treating myself to fresh sheets twice a week.
As to ironing - I don't do that but it seems to me that folding a sheet into a manageable size and ironing through several layers would work quite well and take very little time. I do sometimes iron pillow slips especially for guests or when it's very warm in the summer. Also fold them, put them in a plastic bag and store in the freezer until just before bedtime - nothing better than a cool linen case. No deep freeze here but know people who keep pillows in there for the same reason, at the peak of summer.