I played with "Reminders" app. It allows sorting (as you do for aligning cities in your weather app). And u have the option to choose a time to be notified/reminded to view it. Reminders have titles, then u can list related items under ea title as sub topics; these subs can later be moved to a NEW "title" if you need to subdivide (e.g., if a title is "To Do" but your list gets long and you want to break down the To Do list into "Shop" & "Chores"). This is done by tapping "details" then "list" when you're on the To Do page.