An inner life has stock in it, and stock has to be laid in during ordinary weather. Music you know well enough to hear without playing it. A view you have walked often enough that you can go there behind your eyes on a bad afternoon.
None of it seems useful at the time of acquiring. It looks like idling.
Then a hard week arrives and you find you are not empty-handed — that there is something in there to reach for, put down years earlier by a version of you who had no idea what it was being saved for.