Voting by mail? Did you know that 28 states use signature matching to verify ballots?
They compare the signature on your ballot with one they have on file from voter registrations, ballot applications or the D.M.V. California apparently does this. NC apparently does not (we have to have two witness signatures, instead (Edit: Actually just one witness. Wasn’t it two for the primary?? Definitely appears to be just one now)).
All but 4 of those states have a process to allow voters to fix a mismatched signature. This process is sometimes referred to as “curing.”
So if you’re voting by mail, you may wish to be careful with your signature. Or if you think your signature is inconsistent and you’re in a swing state (Edit: or you’re voting for any close race that you care about) and don’t have a lot of confidence in the cure process and want to be extra sure your vote is counted then you may wish to vote in person.
Wondering what your state does? There’s a color-coded map near the bottom of this NY Times article.
I had a thought that there was some federal decision stating that all states must give voters an opportunity to fix invalid ballots, but I can’t find anything indicating such. Somewhat related, this WRAL article discusses uncertainty about how NC will handle incomplete vote-by-mail ballots.