In modern construction, wall studs are usually either 16 or 24 inches apart. For exterior walls or load-bearing walls, studs are usually 16 inches apart. When the wall is interior and not load-bearing, it is okay to have studs that are 24 inches apart.
Studs in walls are what support the weight of a structure, and they are vital to the structural integrity of the building. Typically studs are made out of two-by-four or two-by-six boards. When trying to evenly displace studs across a length of wall, if the length cannot be evenly divided into 16 or 24 in increments, it is always better and safer to put in too many studs than to have too few studs.