Any interval you like
Every 9 days. Every 4 weeks. The third Tuesday. Not just daily and weekly.
Real routines don't fit a dropdown of five options. Filter changes, quarterly reviews, fortnightly one-to-ones.
How to use it
Three places make one, all with the same builder: Tasks → Repeating → New repeating task; the Repeats tickbox in the add-task form; and Repeats under Other settings on a once-over card.
Frequency gives you five choices: Daily (the default), Weekly, Monthly, Annually, Custom. Custom opens on Repeat every 3 days — the pair every calendar app shows you, a number and a unit. The refinements follow the unit rather than the button, so "every 3 weeks" gets On these days and "every 2 months" gets Land it on — a date, or an nth weekday, which is how you say "the 4th Thursday of November".
First one on is where the pattern starts counting from, and for a yearly rule it's where the month comes from. Stop after (optional) ends it. As you build, you get it back in plain English — "Every year on the 8th" — with the next few dates.
Tick Repeats on an inbox item and you get a repeating task rather than a one-off, so you'll find it under Repeating instead of in the one-off list.