Ball pythons feel most comfortable in cozy, dark spaces, where they have just enough space for themselves and a little extra wiggle room to spare. Typically, a ball python will prefer a tighter fit than a larger space, but there must be a bit of excess room so that the ball python can easily get into and out of the space in order for the ball python to be perfectly comfortable in it.
Although this space does not particularly need to be a store-bought hide, it is important to have at least one spot of appropriate size that a ball python can go to within its enclosure when it is frightened or tired. This spot can be made with the use of regular household items, like plastic food storage containers, so long as they are opaque and will shield out light, and so long as the ball pythons can get into and out of them easily without hurting themselves. Since all pythons really need is a small dark space or two that they can curl up in while they rest and sleep, you can experiment with different hide-like objects until you find the perfect one for your pet. Make sure you have at least one, however, or your ball python will become very stressed and unhappy.