Some people wash and put the same set back on. Don't know how they get on in winter as they sometimes need to hang on an airer to completely dry. If they go thru the dryer that wears things out quickly.If the sheets only last 2 or 3 years they must be poor quality or have been the only sheets used.
Never use oil for massages ..... baby powder is the way to go .... just as slippery, no stains and your bed smells nice afterwards.I wash my sheets every week and in cold water then hang the in the sun.
I buy good sheets mostly Sheridan. If I buy cheap sheets which are spare sheets eg to use on the lounge if someone sleeps over these are the sheets that get balls on them.
I hate stained sheets they go straight in the bin. This has only happened when my granddaughter's slept over and accidentally draw on the sheets.
Or when hubby and me experimented with oil massages