ONE
How often it’s updated (the older the list, the more out-of-date it is. You want to pay for current names (not outdated ones)

TWO
How they get the data (is it compiled, from a paid directory, from a subscriber list)

THREE
What other kinds of companies have used the list (if you’re in the electronics industry, a list used by toothpaste manufacturers may not be right for you)

FOUR
The products those companies were selling (look for products and services similar to yours. If you sell seminars on HR training, look for lists used by other companies who sell HR training)

FIVE

Whether they rented it again (a sign of how well it worked)

SIX

How often the list is rented (a way to tell if the list is being used too much)