Basketball — allow a little room. Because a player’s foot has to expand as s/he pushes off the ground to make a game-winning shot, allow about ¼ to ½ inch room between the player’s toe and the toe of the shoe. Slipping heels are a no-no, though, because they can cause the foot to twist.
Baseball and softball — toe room when standing. As a player prepares to pitch, hit, or field a ball, s/he is usually in a standing position. There should be plenty of room for the toes to move, yet the shoe should fit snugly since these shoes have firm heel counters.