4 months maybe? The thing is though for like 1+ year back in the day I used to do probably 15-20TB/month back in 2010-2011 with one residential and one business connection and not a peep. The reason being just to get two ONT's at the same address basically requried doing business + residential.
Also several other people were contacted (who used even more bandwidth than I did) and all on the same day. I am pretty sure this is the first time VZ has ever contacted people about bw usage.
Funny enough the 30+ hours on the phone it took me to get upgraded to GPON and other billing/account snafu stuff probably cost VZ more than my bandwidth usage but whatever...