A method includes selecting an arrangement of foam springs, the arrangement that matches user-selected firmness requirements; attaching foam springs to a foam panel in a removable, replaceable manner; and inserting the foam springs and the foam panel into a containment facility. A mattress includes foam springs; a foam panel to which an arrangement of the foam springs is attached in a removable, replaceable manner; a containment facility within which the foam springs and the foam panel are disposed; and a side rail with indentations within which sides of at least some of the foam springs are disposed. The mattress may also include a fabric webbing, attached to the containment facility, within which some of the foam springs are disposed in a removable, replaceable manner; and an attachment device attaching together at least two of the foam springs.