NASHVILLE, Tenn. — As Gillian Welch has promoted her long-awaited new album, “The Harrow & The Harvest,” there comes a point early in each interview when a reporter asks her why it took her eight years to deliver it.

Every. Single. Time.

There’s no good answer, of course. These things occasionally take a while. Welch knows this is not the satisfying, tabloid-flavored answer people are looking for — marriages, divorces, babies! — but it’s the truth.