Time between two dates
I (like others) often need to resolve a question by finding out how old a person was at a certain event. Such as my aunt when she died in an accident, or age of a parent when his/her child was born. Or, how much time elapsed between two events, such as years between birth of children, or years between multiple marriages. I have found this website helpful: https://www.timeanddate.com/date/duration.html
But, it would so much better (awesome) if such was built into FamilySearch. Ideally, click a button in the header to access the time calculator, enter each of the dates by typing, selecting from a calendar, or by clicking on a date displayed in FS. Or, (skip the button) just click on any date in FS, and the calculator pops up.
The calculator would only need to show the Years, months, days, and not all the other detail.
Note: the calculator at https://www.timeanddate.com/date/duration.html requires a month and day, which is not always known in FS. I suggest that if month and day are not known, enter the year only, in which case the resulting answer will be a range such as 12-13 years.