State of NH sends email notification as well as snail mail 6 weeks before license renewal. They are now trying to do license renewals by computer. You use the same picture from your previous license, cannot make any changes to the license and you pay by debit or credit card. This is how I renewed my license last year. Will have to go to the DMV next time to renew because they won't use 10 year old pictures! Guess the DMV doesn't want us to look young forever!
Town (at least the one I live in) sends snail mail notices 2 months before registrations (plates) expire. (In NH you have to pay both the town and the state for the privilege of driving a car).
I must say that dealing with the DMV here in New Hampshire is an absolute pleasure compared to dealing with the DMV in Massachusetts. It was an all day event when you had to go to the registry in Boston!