Continuing on the "cleaning for your mental health" theme, there are several tasks that only need to be done twice a year. Here are a few of them....
Clean the oven. Much easier if you have a self-cleaning oven...
Vacuum out your heat registers.
Clean your leather furniture.
Flip your mattresses.
Clean your throw rugs.
Dust your bookshelves, and the books.
Replace the box of baking soda in your fridge.
Clean out your freezer and discard the old stuff.
Clean your bedspreads.
Clean your stove hood.
As the seasons change, clean out your closets and give away any clothes that you don't wear.
Just set a day and take care of these tasks all at once. They'll be over before you know it!