In my native language we don't have gendered pronouns. When I talk I have to use extra brain power to determine which pronoun to use as I was raised in an environment where this was a non-issue. It is really hard asto think about whether to use he or she if you were simply not raised up to care about genders when talking about someone in the third person.
In English classes we were usually told to use he in translations from our native language, unless we knew that the person is female, and this. This default did lead me to some issues when I moved to the UK as I did use he simply too much, - even when I actively knew the other person being a female. I started actively using they afterwards, as that was definitely the easy way out for me, whether I knowknew the gender (and preferred pronoun) of the other person or not.
However I know that in English the use of they can be disrespectful to some group of people. Women might object to the usage as it removes their gender from conversationconversations, which especially in male-dominated fields can be problematic, as the reader might assume a male behind the pronoun. SomeAlso some trans people might also object to it as it can be one kind of misgendering, as it can mean you are trying to avoid referring to them using their new gender.
I am always trying to use they in conversations both written and oral. However if anyone objects I'm happy to use their version as well, as that is the nice thing to do.