hi bri,
Running AIS here, and just went thru the same thing you are seeing now. Open the gui, see the countdown to expiration. At least it wasn't a nagging daily popup toaster, never got that.
Not a big deal here as I was able to wait until within the last 24 hours to renew the subscription, and by doing so, got 36(6) days, an extra day, on renewal. Didn't want to be annoyed by the notification, so didn't open the gui anymore than I needed to, which is less than once a day, or three-four times a week at the most. Situation we're looking at is an avast! user that uses their system maybe once a week or so, so they're covering that user scenario little bit ahead of time in case that is the case, or the user is out of town for some reason or another and not using their system because of that. Better a little early than too late.
The way the renewal licence process works is it is effective on the date of purchase, and not on the day you activate it. Your year-long protection begins when you buy the licence. So you would want to wait until the last minute to purchase the licence so as to get another full year of protection and activate it at least a couple of hours before the old licence expires. That way you should get your 366 days.