As mentioned above the plans expire at midnight eastern time zone & are 10 calendar days (with the first day a partial day from time of purchase until midnight that same day).
The other aspect is that the add on starts immediately on the '2nd' step (add funds 1st then 2nd step is to 'buy' the plan & it starts right away & can't delay the start to the next day or next week etc). So best time to buy is in the morning as you are leaving.
In my case i was going to USA for 12 days.
I knew the close to border areas really well & given that we usually leave late morning I figured I'd buy it on the morning of next day (or super late after midnight). That way it would last for the 10 days I was farthest from Canada (& the "full USA days" not the partial day I left or returned).
TIPS:
- you can download you trip into google maps before you leave so u use less data
- it's a 2 step process (1. add funds, then 2. select & buy add on)
- it starts the day you buy it (so do it real late -after midnight or next morning)
- changes to your route or if going far -you can use hotel or free wifi to update/ download new maps/ route areas.
- the connection should occur automatically once you loose PM signal - your phone should auto search & connect to USA provider (ATT i think)
Experience:
- we travelled for 12 days, 10 of which we had the add on & didn't use that much data. (In fact listened to streaming radio on last day). But we did updates/ search routes in hotel using wifi (or coffee shop etc).
- connections were usually great (except in rural areas of Utah/ etc) & good the the Disneyland app.
