testing our website with https://developers.google.com/speed/pagespeed/insights we found that the utag.sync.js and utag.js have 5 minutes of expiration time.
Is it possible to increase the Expires value for scripts served by Tealium?
If possible, what is the maximum recommended value?
No, it's not possible to increase this value. It's set as 5 minutes to guarantee that the latest utag files are always served when you do a publish.
Most of the time, the utag files will be served from cache anyway, and if the file has not changed, it will not be re-downloaded. The 5 minute expiration is simply a check to see if the file has changed, and it will only be re-downloaded if this is the case.
Hope this helps to explain things.
Check out our new Swift integration library for iOS, macOS, tvOS and watchOS: https://github.com/Tealium/tealium-swift with updated documentation https://community.tealiumiq.com/t5/Swift/tkb-p/swift.