Sarah gets a text at three in the afternoon. Her neighbour's back has gone again. She is up against a deadline, but she stops, picks up the shopping, climbs the three flights of stairs. Later she works out that this is the fifth time this month. Later still, she wonders whether she minds.
She would not call it virtue, which would make it sound cleaner than it is. We take care of one another because we need each other, and the need comes mixed: the hands that carry the shopping up the stairs also pull doors shut, and the voice that rings to check in stays on the line to gossip.
You can watch it move along a street. The woman who waters the plants in the window of the empty flat next door has a good look round while she is in there. The teenagers everyone complains about carry the loudest complainer's shopping up and scatter birdseed from their pockets on the way out. The man who speaks to no one sets his bins down without a sound, so as not to wake the baby upstairs, and the woman who runs everything leaves sharp little notes about the noise and feeds the stray cats nobody admits to owning.
Most of it travels under other names. The book group is also a way of checking everyone is still alive, and the residents' meeting is somewhere to belong on a Tuesday; the long argument about the parking is also about being seen by the people next door. We organise bake sales and form tenant unions out of principle, and because we cannot manage alone and would rather not say so. The labour is shared out much less evenly than the need. Some people become the street's answer so gradually that no one remembers asking whether they agreed.
For eleven years a lunch club has run in the church hall on Thursdays: soup, a raffle, a lift home for the ones who cannot manage the hill. Then the hall is sold for flats, and suddenly everyone has a position. Who was taking care of whom? The volunteers who cook, the diners who keep each other coming, the church with a roof to mend, the developer with the housing the street also needs, the council deciding the planning application. Everyone can name a need, and only some get to decide which one survives.
Refusing to keep score can be how the same person ends up paying every time. The parent who gives everything may be fastening a leash. And the person who is always there turns, over the years, into infrastructure, praised by everyone and relieved by no one. Calling all this an ecology can be a way of deciding not to mend it.
And still Sarah climbs the stairs, the bags cutting into her fingers, past the landing where the bulb went months ago. This time. The need does not decide who answers it, or how often. The fifth time matters. So would a refusal.