Okay, correct me if I’m wrong:
In the Pathfinder Universe, souls travel along the River of Souls after death, then hang around Pharasmas Boneyard for a while, get judged and then get send to whichever Outer Sphere plane matches their alignment. There, they become so-called petitioners, suffer/enjoy themselves for a while and with sufficient piety/malice/effort, eventually turn into a plane-appropriate outsider.
Now, has is ever been stated how long this process roughly takes? Years, decades, centuries, millennia? The only reference to time I found was about hammer archons:
Those archons who continually proves themselves in battle, either by striking down hordes of demons or by holding back a single pit fiend long enough for reinforcements to arrive, may get promoted to the rank of hammer archon. This process can take centuries, even millennia, but the lawful-aligned outsiders would brook no shortcuts. Many hound archons and shield archons with martial inclinations ceaselessly endeavor to rise to the heights of power that being a hammer archon represents.
But this is more about “rising in the ranks”, so to speak. And “brook no shortcuts” implied that shortcuts are apparently a thing(?).
(Honestly, the most interesting question to me is – would it be feasible for someone’s wise old mentor figure to return as an archon or for a former BBEG to reappear as a devil? I know they don’t really keep any proper memories of their old selves, but it would still be cool!)