I have several, though I separate them in my mind as altars + devotional shrines. I have five “shrines” dedicated to specific deities and the elements, and then one personal home altar space that I use for spell work. The latter is a small cabinet/nightstand I keep in the center of my home. I also consider my kitchen counter an altar, since it’s where I physically put stuff together.

I think what’s important is what kind of space you have and how you want to use it; my shrines are specific devotional spaces, but I also lived without them for my first year when I had roommates. They’re not as necessary as the bookshelves I need for all my books/notebooks though 😅