Follows the same guidelines as typical wire fill calculation
Leaves room for future expansion
Maximum distance between each CC under floor joists is 16" (when using under floor joists, the maximum distance, on one side from any wall, joist, pipe or ductwork is 12")
Maximum distance between each CC along floor joists is 30"
Maximum distance between each CC above ceiling joists is 24"
Wire fill per hole: No more than (3) of 14-2, 14-3, 12-2, 12-3 romex. No more than (2) of 10-2, 10-3, 8-2, 6-2 romex. No more than (1) of 8-3, 6-3 romex and any SER up to #2. Unlimited low voltage, data, phone, cable