I am interested in trying Google FI. If I request an invite do I have to activate on Google Fi right away or can I hold onto the invite for a couple months before activating. I have no idea how long it takes to get the invite and I have 3 months left on my contract with another carrier, but I would like to activate the google fi account for one month overlapping my final month with current carrier so I can test the service where I live and work (and play.)