Date and Timestamp in registry and relevance

I would like to create a fixlet that creates a custom registry string value of the date and time the fixlet ran and then a relevance that retrieves any occurrences of this value that is over 2 weeks old if that makes sense so:

HKLM\Software\MyCompany
LastContact=“20160513.17:00:00” or something similar (not too picky about the format as long as it is readable by the relevance below).

Relevance that shows any computers that have a date in LastContact that is older than 14 days old.

The purpose of this script is going to be to determine if/when remote users connect to our network via VPN and to remind those users that they need to do so if they are not connected within the last 2 weeks. I am planning to make the fixlet relevant ONLY if they are connected to the VPN.

Probably be easiest to use a Custom Setting (which itself is stored in the registry, but more portable this way)

setting "LastContact"="{now}" on "{now}" for client

Relevance:

not exists setting "LastContact" whose (now - value of it as string as time < 14 * day) of client

Thank you Jason that will work.