If you don’t know someone’s pronouns, it’s always better to ask. There’s no harm in asking, whereas making assumptions about someone’s pronouns based on their gender expression can be harmful. Some people will feel awkward if you guess the wrong ones and won’t correct you, leading to a rift in communication. And by not jumping to the conclusion that a masculine person uses he/him/his, you can help others feel comfortable expressing themselves too.You don’t often have to ask for someone’s pronouns more than once. While some people use more than one set of pronouns, it’s their responsibility to let you know if they are changing, just as it’s your responsibility to use the pronouns they’ve asked you to use.