There is a setting on the Access Education People system determining TOIL expiry. Follow the below steps to change this:
Go to Setup and click Settings.
Click System Settings, then Global.
Search Time Lieu and click the setting called Time Lieu Expiry (Months).
Type in the number of months in the Integer field. This will be how many months since the TOIL's date when it will expire.
Click Save.
If you want TOIL to never expire, type in 9999 in the Integer field when changing this setting.