Spring cleaning is a ritual in many households—for good reasons. During Fall and Winter, we spend hour after hour confined to our homes, often doing things that make our homes spaces that amp up our stress levels. After Spring cleaning, they’re more relaxing places to spend time with family and friends
We continually accumulate stuff and dealing with it is part of Spring cleaning. Stuff isn't trash, it's torn out magazine articles set aside to be re-read later, gifts that haven't quite made their way to their final resting places, and cozy nests created to fight off the Winter chill—in a word, it's clutter.
Clutter is mentally exhausting. In our less developed prehistory, we needed to continually survey our environment, to make sure that nothing that found us appetizing was approaching. It's easier to review a less cluttered environment; danger stands out more clearly. That survey behavior from long ago is probably at least one of the reasons that we prefer less complex wallpapers today. Each time we review a space—and we still do scan the environment each time we enter a new one—our eyes focus on each item there. Clutter makes it take longer to complete an "environmental sweep."