Omnifocus has repeatable tasks and you can pick whether they repeat based on the due date (once a month, like the mortgage), or on completion date (I use this for cleaning chores, so if I'm late to clean the bathroom, don't tell me to do it in 2 days because it's Saturday, tell me to do it 1 week from now)
It does, as does Todoist and other task managers. But it's never a first class citizen and takes a backseat to one-off task management. For many, these features or even Google Sheets or the Notes app is sufficient. It wasn't for me, though.
