When to stop using "Mr." In an email chain

Question

So I have been emailing my future employers (for an internship) for about a 3/4 of the year which has resulted in many emails being exchanged. When I first responded to their email, I addressed the recipient as Mr. Employer. Using Mr. In general makes me a little uncomfortable because I don't want to appear brownnosy, but also don't want to offend anybody and also would like to appear polite by using Mr. So I would use mister in an email, and hopefully don't have to respond many more times to continue the gesture.

Is it ok or expected to switch to first name over the course of a lengthy email chain? And should I have even used "Mr" in the first place?

Edit: I am based in the US

Answer 1

You don't mention what country you are in, but this is strongly dependent on culture and generation.

In english speaking countries, look for clues in their email responses. If they're signing off with just their first name, or addressing you by your first name, respond in kind. Some cultures are more structured, and it's considered polite to wait for the more "senior" party to explicitly invite the use of informal modes of address.

In general, start a correspondence in a formal tone, and gradually move to informal if appropriate. Very few people will be strongly offended by a stranger addressing them as Mr., Ms., or by their title. They may eventually say "Please call me Bob", but that's usually a friendly invitation, not a rebuke. On the other hand some people are quite offended by strangers using their first name, or omitting their title.