One illustrative method of controlling wireless network resources for data sessions involves the steps of identifying IP address usage for mobile stations operating in a wireless communication network and causing a data inactivity timer of a data session for a mobile station to be set to an initial value that depends on the IP address usage. The data inactivity timer is set to a relatively large value when the IP address usage is low, but to a relatively small value when the IP address usage is high in order to expeditiously release underutilized network resources. The data session may be Point-to-Point Protocol (PPP) session for which an IP address is dynamically-assigned to the mobile station.