Why not have a control person in your IT unit that logs each page/script into a db and records the last time that updates were made. Then you monitor that db to check what scripts are coming up on a predetermined time-elapsed value and print a report.
This avoids the emails, the effort to place some new logic into existing code, and allows for a single control point as well as variable expire dates should that be necessary.
date last updated
(a value that represents the lifetime of this script before it requires review)
responsible unit (?)
Then you have a cron task that queries this table looking for any records that the date last update + the time value that calculates out to an upcoming expiration that is within your desired window.