The restrictions for free users is in the number of IP lookups per domain limited to the 300 lookups (300 visitors) per day. After you reach limits, our API will stop providing geo information for that day and next day you will again have 300 lookups available. This is good for all small websites who are at the beginning of their careers or in development. But as you grow, you need to be unlimited.
How does a lookup count?
Any change of IP address on one domain is considered as a new lookup. Every change of IP address pulls new geo information through our API.
But the plugin also has its own algorithm for caching geo information on your server for each visitor individually and that cache has its own expiration time. When the cache time expires, a new lookup is made.
Defining the expiration time of that cache is done via a special constant CFGP_SESSION.
The reason for this cache is that one IP address can be in another geolocation after a certain time.
If this caching is a problem for you, change the caching time to a longer period of time.
These constant must be modified within your wp-config.php file:
define( 'CFGP_SESSION', (60*24*30) ); // Set session to 30 days (60 minutes * 24 hours * 30 days in the 43200 minutes expire)
Also inform yourself about: What do I get from Unlimited License?