If I have 3 openings, I may buy 5 states. If I have 5 openings, I may purchase 8 states. But that depends on how many recruits are there. At DIII, I can't afford to scout more than one large state.
Sometimes, I do a tally. Say, I need a PG. I do a search for under 100 miles and write down how many PGs (including potential dropdowns) are in each state. Then i expand it to 200 miles and write down how many are within 100-200 miles from my school. I repeat it for 300 and 400 miles. That gives me an idea of which states to recruit for that position.