When was Roshi at his prime?

[Power Level Guy]

Given that he references his and Tsuru's younger selves fighting Piccolo Daimao, it's logical to assume that was his peak as far as the original series goes. It's likely he could have surpassed that if he continued training for the 23rd Budokai, but he lost the drive.

It's funny, the Chonzenhu has Roshi as 18 years old when he trained under Mutaito.

 

[SSJ2]

The guy peaked early lol

 

[Power Level Guy]

The guy peaked early lol

Haha for real!

Perhaps after running into a monster like Piccolo Daimao, you just say, "Meh, this is good enough."

 

[SSJ2]

He probably figured there was no way anyone could come close to that level again.

 

[Power Level Guy]

He probably figured there was no way anyone could come close to that level again.

Which he was right about, until an alien came and changed the game.