For the folks who do not wish to fiddle around with expiry and termination of account dates but wish to retain their "home" phone number, how about an add-on that costs $10/calendar month and is purchased in 3 - 9 month increments. To ease the back end burden I suggest it be a 1 time cost (ie. $30-$90) and take effect IMMEDIATELY. Dead easy for travellers to figure out. Account is dormant during that period and cancelled if no payments received prior to the End Date.
I'm too frugal for this plan, but the options using the regular plans all involve staying in touch with your account within 90 days of expiry.