I can’t tell you how many times I had ended up with little to no blankets after sleeping 4 four hours. Eventually, spouse and I decided that we would get two full-size blankets for the bed so that we could each have one. This has prevented so many restless nights.
We have started using the spare room whenever one of us has a cold, has a different schedule, or we have something important the next day. But for other nights the simple pleasure of waking up next to one another is worth a small dip in sleep quality.