Whether you will be charged for the replacement of datacenter IPs depends on the reason and the number of IP addresses you want to change.
In case the customer requests to replace more than 20% of the total amount of Datacenter Proxies within three months, the customer shall pay the additional fee according to the price per IP.
The above is stated in the agreements. However, we try to be as linear as possible and retain the right to only apply these terms for clients who abuse provided resources on purpose. You can always discuss your situation with your account manager.