How long does it take the narrator and his neighbor to mend the wall in Robert Frost's "Mending Wall"?

In "Mending Wall," it takes the narrator and his neighbor a day to mend the wall between their properties. We know this, because the narrator states:


And on a day we meet to walk the line
And set the wall between us once again.


It depends on your perspective as to whether this is a long time or a short time to spend mending a stone wall. A day may not seem that long in the scheme of things, but from the narrator's point of view, it is a waste of time to mend the wall at all. He doesn't see any reason for them to keep a wall between their two properties because neither of them has any livestock that can wander away and damage each other's property. However, the neighbor is quite adamant that the wall must be repaired each spring. For the neighbor, tradition dictates this repair because his father taught him that "good fences make good neighbors."