Asking a random person for their kwh usage is not realistic. Dollars per month change (where they haven't changed driving drastically) is more practical.
But you aren't asking random people. You are asking EV owners on Hacker News.
In general, EV owners are pretty savvy. More than most actually know what they pay per kwh and have a pretty good idea of their consumption. The biggest common mistake that I see is net vs gross.
