How long should a successful rebuild take?

3 years. Payton did it twice. He started in 2006 and won it all in 2009. They again tore it down in 2014 and was elite by 2017/8. The problem is the QB position.
LOL, 2014 wasn't a teardown---we were in the divisional playoffs the year before and lost to the eventual champs, why would a decision be made to tear it down after that? Brees still had our offense in the top 8 or 9, the defense just fell apart. Greer had to retire, Keenan Lewis & Delvin Breaux were hurt, we bet the farm on defensive free agents that didn't work (Bryd, Paul Kruger, Dannell Ellerbe). Payton & Loomis weren't about to get rid of everyone while Brees was still top 5.