Comment by jraph

Trans people are not usually hostile to someone making genuine mistakes. It becomes an issue if one makes them intentionally, or if one appears to be careless.

It's also ok to ask trans people what are their pronouns. They should be glad most of the time.

About cis people, I don't know. I don't have much experience in the topic. I've never seen anybody misgender a cis person. Sometimes there is a doubt but it's vanishingly rare. It's also uncommon to ask a cis person their pronouns, and I believe a cis person won't expect to be asked this because for them it should be obvious what their gender is, though it would be logical to do so because you are not expected to notice a trans person is trans and some places push for it.

I personally won't explicitly ask pronouns unless absolutely necessary and didn't have the chance to pick the information up passively. I certainly don't need this on the internet.

On the internet, the rule is simple: you should not use a gendered pronoun to refer to someone without checking first. "they" is safer if you don't want to spend time checking their profile and sometimes you just can't know. That's what I do most of the time.

Now, trans or cis, if you keep misgendering the same person, it's a bit like using a wrong name several times with the same person. People don't usually like this. Since gender identity is (unfortunately; my opinion) a big deal in our societies you have no choice to care if you don't want to piss people off. It's general politeness, if you don't want to appear rude, you need to care, remember, etc, just like you need to remember the name. Though forgetting names is quite generally understood and accepted. I'm of people who don't easily remember names at first.

tl;dr: I use "they" on the internet or check the profile. In real life, I try to pick it up and remember the information. It has not happened to me that I misgender someone, but I consider it is fine once but will not make the mistake twice.