I know Marriott gives you 2 years for "account activity" before it cancels your account per the TOS. Does this mean a stay once every 2 years or is it like Skymiles where any account activity counts to keep your account active? I have 6 months yet but I've been on a dry spell for work travel.

It would be a good idea if Marriott, like Skymiles, would post an expiration date in its e-statements or online check-in because I haven't seen one.