Keep the day selected even when you switch the month or year (so it’s still highlighting the same #)
Leave the day highlighted even when you switch around the months or years (e.g. if due date was Nov 13 2023 and I want to change it to next year because it’s an anniversary, even when I change the year to 2024, let the day stay on 13)
For repetitive tasks / events, this is helpful since especially if it’s not like a birthday or something you remember, when it de-selects the day once you change the month/year, it gets confusing and you have to recheck the date and do it again.
Also just simpler for repeated tasks/events since you can just change the month/year without having to reclick the day.