As coming from country with actually working IT, I always wondered about those year and month tags... I get my yearly tax directly as bill to my bank...
That's not what the tags are for though, the tags are registration tags indicating your plate is active. In Massachusetts, it's $30/yr for active registration and the plate cannot be renewed without active insurance, etc.
So, if you fail to renew your insurance then you won't get a new registration sticker and your plate will eventually be easily identified as lapsed. The automated systems will see it immediately – and they do! But we still apply the sticker for manual identification.