I think there are some things that should be shared up front on the first or second date, like not wanting kids, not wanting to get married, or wanting to keep finances seperate if you do get married to someone. These are often deal breakers that are impossible to compromise on and not worth wasting your time even casually dating someone that isn’t on the same page.

There are other more sensitive things like a serious physical or mental illness, or family trauma, that you might choose to disclose more slowly because they might not impact your partner very much at all depending on how you manage them.