Not actually zero. Closets stuffed full of stuff means more time wasted trying to find what you need and more time spent finding a place to store a new item.
My point was that you could try to think of your storage unit as if the size and monthly cost of your home was more flexible, i.e. you can just pay 2% per month for 2% more space.
When you chose your house there were presumably several options with different amounts of storage space at different price points. You could just treat the addition of a storage unit as increased granularity between those housing options.
Storage space is really just tacked proportional to bedrooms, for the most part. My house has what feels like a bunch of extra space because I wanted enough bedrooms for my family. They didn't need to come with so much extra, that's just how they build homes with more than a few bedrooms now.
The stuff I use every day (work/entertainment electronics, cooking stuff, some furniture, and clothes) can fit into a small-ish apartment easily-enough.
But the stuff I use occasionally (like camping gear and car-fixing/woodworking tools) would not fit also into that same apartment, nor would my collection of hobby-related stuff like my (small, but non-zero) collection of vintage audio and computer gear.
I mean: I'm not hoarding MicroSD cards here. I, like many others, have things that take up space.
In order to keep these seldom-used things out of the way while maintaining the hope of having a tidy, presentable home, I need a place with a garage or a basement or an extra bedroom -- or a storage facility. Those things all tend to cost extra.
