On every work page, we hash your IP address together with your browser's user agent before we store anything. That hash lets us recognise a repeat view of the same work within a day, so refreshing the page or running a script against it does not inflate the count. The address itself is never stored, only the hash, and hashes are deleted automatically after 30 days.
On the contact form and the submission form, we hold your IP address in memory for a short time, to limit how many messages or submissions can be sent in a short period. It is not hashed there and not written to any persistent record. It is only kept long enough to apply that limit, and clears when the server restarts.