Manufacturers design handheld broadcast spreaders and broadcast spreaders that require walk-behind propulsion. Drop spreaders also require you to push them from behind. A slit seeder contains narrow tines that make grooves in your lawn as you propel it forward.
Handheld broadcast spreaders drop fertilizer in all directions when you turn a handle. Broadcast spreaders distribute fertilizer in a circular radius as you push them. Drop spreaders distribute a continuous line of fertilizer as you push them. Slit seeders drop seeds in the grooves and then pass over the seed with a metal roller that presses it firmly into the soil.
When using a drop or broadcast spreader, the University of California recommends overlapping your path to prevent stripes on your grass and uneven distribution. When using a slit seeder, the University of Illinois Extension recommends that every second pass remains perpendicular to your first seed distribution path.