Creatively when should the Undertaker have retired?
After Wrestlemania 26 with Shawn.
After Wrestlemania 28 after having his last classic match.
After Wrestlemania 30 when the streak was broken.
After Wrestlemania 46 to pass the torch to Roman Reigns Jr.
After the streak was broken. The story was done and there was no need to beat Bray Wyatt the next year.