Custom Workflow Trigger

Hi All,

Does anyone know if it is possible to create custom workflow triggers. I would like to create a trigger that evaluates an expression on Page Load. I am attempting to create a field which advises users to verify customer details that have not been checked for over 6 months. My company has taken the decision not to ask for this information on every contact. We do have a field which shows the date the information was last verified but want to make it obvious that verification is again needed.

I already have a workflow in place which updates the field when any details are changed but this will not work for each time the page is viewed.