Executing JavaScript once for an entire Storyline course

Hi guys,

I have been exploring the functionality of expiring a course in Storyline once it's reached a certain date (using the LMS for this is not always possible). Now, I know this is not something that is built into Storyline (like Captivate) and I have found a script that runs off of a trigger, in my project, to retrieve the system date and compare it to my expiry date using variables, which works fine.

My question is this -   where do I run this script? 

I can run it on the first screen as a user accesses the course but this doesn't account for the resume functionality, i.e. users continuing their 'session' will pick up from where they left off, bypassing the script. I don't want to force the user to start the course all over again every time.

My other option is to insert the trigger and script into the Master Slide so that it runs on each screen, which means it doesn't matter where the user picks up from. But I don't necessarily need the script to run on every screen as the user works through the course, only once per 'session' really. Does this matter, would the script running on each screen slow down the course or 'break' the course?

Thanks!