We use a doona with a fitted sheet underneath. Fitted sheets are so much easier to put on. I don't have to worry about those hospital corners, and climbing between furniture to fold those corners. We have just a doona cover. This cover is supposed to replace any need for a sheet. I am sure that I would get all tangled up in it anyway, but I cant see any need for one. We change our doona cover every two weeks. Sometimes it is longer over winter when it is hard to get bedding dry.
When I change my matching coloured sheets. I have about 12 different coloured pre of sheets. 1/2 of them match 1 doona, & the others of cause, match the other patterned cover. 1 cover is pastels, the other is b/w.
I change my doona/duvet/eiderdown cover every couple of weeks as a rule. (I have five) I am weird . . . I have an empty white cover under the doona and also proper sheets on the bed. I could not possibly sleep under just the doona. - I need to be tucked in. The white cover protects the sheets in case the dogs get on the bed and start trying to nest. LOL. So, in summer, I am effectively sleeping under 5 sheets if you count the two empty doona covers. There might be two days a year that I could possibly be too hot.
annfi has just jogged my memory that I also have a cotton blanket under the doona . . . . I am a cold frog. I don't use the matching pillow cases either as they are usually too thick too be soft and comfy, I use the ones that match my sheets.
I use a doona cover without a doona in Summer, with a doona in Winter. I often use a cotton blanket and always a top sheet as well. My sheets are washed once a week, but my doona cover probably goes a month or more in Summer and probably two months in Winter.
My doona and it's cover is aired in the sun while my sheets are on the line. I don't like to wash them too often as they have embroidery or lacework that would look worn quickly. The pillowcases that match the doona are not slept on but on pillows that are on the bed during the day.
I don't use my doona as I rarely feel the cold but when I did use it, I always had a top sheet underneath and regularly aired it in the sun so didn't need to wash it as often. Sadly it sits packed away in the linen press in case someone needs it.
Gosh! I have not needed to use a Doona for at least a year with the shockingly warm weather pattern here in North Qld! HOWEVER....when I did use my doona in winter I ALWAYS had a top sheet as well,and I would wash the cover each week. My dogs share my sleeping space so I have a lovely dark green towel which I lay across the foot section of the bed.I am still only needing a top sheet ,though I expect (at least,I HOPE!!!) I may need my doona this winter at some stage!! I love to snuggle under a doona when it is a bit chilly at night!!