you definitely can set global variables to time now(). here is bruce's post explaining:
here is an example of a rule that I use to track presence:
RM Example: Selective Presence Notifications for Two Users - #3 by jrau272****
try to remember that hubitat is an event based system. when writing rules, try think of what events you need to monitor. it doesn't have the hardware to constantly monitor everything, so you have to be careful with how you construct your rules to keep things from getting overloaded.
