I'm the type who doesn't force it. I just "let it happen" however it wants to.
Now those who force a patina? Some just like the look and want to hurry along the process and don't want to wait 6 months to a year or more for one to develop. Others do it because it does sort of give the knife a more rust resistant property once the patina is set.
To each his own.
My #55 with a natural aging... Its been 4.5 months as my nonstop EDC. The backspring especially has taken on a dark gray color.