Re-timing Revolvers

Had an interesting conversation with a friend today. We were discussing the frequency with which it would become necessary to re-time a revolver.

His take was about every 1500 rds....I took issue with it based many upon the fact that most revolvers I've had have way more than that through them without any issues.

So my question is

1. What are the symptoms that you see from a revolver...telling you its time to go see the smith? Lead blowback while firing? I guess that's telling you that the cylinder is not properly lining up with the forcing cone?

2. How many rounds does this typically take? For example...I would imagine an ICORE shooter would have to be real good friends with a gunsmith if this needed to be done every 1500 rds...As I'd imagine 500 rds a month would be pretty average for usage

For the sake of discussion...we'll say S&W revolvers

What say ya'll?