Repeating expenses and periods

Most nests never need to think about this. You add expenses, the balance runs, and when everyone has paid up the period closes on its own.

Because your nest grew.

You had "Only once per period" turned on for a repeating expense. That setting is on by default for nests of two people, and off by default once a nest reaches three or more, because it stops working well at that size. When your nest passed two members, Eider turned it off and unchecked the box on your repeating expense.

What changes from here: that repeating expense now lands in your nest's current period like every other expense, instead of opening a new period when it comes due a second time.

If you still want it, you can turn it back on: Settings, then Nest, then Periods, then "Allow repeating expenses to open new periods." The checkbox reappears on your repeating expenses and you can tick it again. Read the next two sections first, because the reason it was turned off still applies.

Some expenses are large and land on a schedule. A mortgage, rent, a car payment. If one of those comes due twice inside the same period, the balance reads as though you owe twice what you really do for that month, and the period gets harder to settle rather than easier.

Turning this setting on adds a checkbox to each repeating expense called "Only once per period". When that checkbox is on and the expense comes due in a period where it has already been added once, Eider opens a new period and puts it there instead. Each payment gets its own stretch of time, so the numbers match the month.

A period closes only when everyone is square with everyone else at the same moment. That is a much bigger ask than it sounds, because it is not about people, it is about pairs.

With two people there is one pair, so a period closes the moment you two square up. With six people there are fifteen pairs, and they all have to be square at the same time. In practice that almost never happens in a nest that keeps running. Somebody always owes somebody something.

So in a nest of three or more, a period tends to stay open indefinitely. That is fine on its own: the balance just keeps running, which is what a shared household usually wants anyway.

It stops being fine when something is opening new periods automatically. Each new period starts its own balance, the old one never reaches zero and never closes, and they accumulate. Worse, the totals stop meaning what they look like: you can owe someone in one period and be owed by the same person in another, and because each period is anchored on its own, those two amounts do not cancel. The nest ends up displaying a much larger outstanding figure than anyone actually owes.

That is why the setting is on by default for nests of two, and off by default for nests of three or more.

When a third member joins a nest that had this on, the setting turns itself off and any repeating expenses using the checkbox stop opening new periods.

Whoever set up each repeating expense gets a notification so nothing changes behind their back, and they can turn the setting back on if the nest still wants it.