You should always let the container determine its contents.
For example, a carton of milk holds 8 ounces. Try and fit an ounce more, and it will be full to overflowing. Similarly, you don’t want to fill your home so full that it is overflowing.
This concept applies to all the containers in your home, and your home itself. Let each container give you a natural limit for the amount of contents it can hold.
To this end, I encourage people to only keep as many books as their dedicated book shelves can comfortably hold. The floor is not an option! It’s better to edit your collection (old textbooks and encyclopedias are excellent candidates for removal) and have the truly beloved books fit.
Your closet and drawers are the containers for your clothes—only keep as many garments as they can comfortably hold. Your fridge, freezer, and pantry are the containers for your food—the same rule applies.
And if you have a long-term, off-site storage unit that you are paying for, I strongly encourage you to address the items it contains. Try to edit them down so that they all fit into your actual living container, your current home!
Let me know which of your containers are currently overflowing, and how you’re going to get their contents in check.