@Jd63,
Yes, you should wash the blankets and duvet covers between each stay, but I recommend that you put only the type of bed covering that's appropriate for the current weather and length of stay, and not leave a large assortment of bedding for the guests to access. During this time of year at our Atlanta spaces we place duvet covers without inserts on top of the sheets. When the temperature is cooler, we exchange the duvet covers for comforters or put inserts in the duvet covers, and provide blankets.