Wrens - Postscript

When the Wren chicks in our nest box fledged, the parents encouraged them to leave the area as soon as possible.  These birds disappeared from our garden.

Yesterday late afternoon, the two parent birds came back, along with three chicks, to explore the nest box and the surrounding shrubs.  One parent and one chick entered the nest box and stayed for a short time.  They all then flew around the garden, in and out of the hedges, then they were gone again.
Are the parents checking out the box for a second brood, or is it just a way of introducing the chicks to the local territory?