Excellent advice. I've been playing with 100X buy-in for years without any regrets. Though I do cheat once in a while whenever I reach an imaginary goal. To celebrate I'll get in a game under 50x. If I win, I play again, and again, until I lose. Then I go back to the 100x. If I lose, I immediately go back to the 100x.
I mostly play SNGs. Started on Ignition a year and a half ago with $25, and now my bankroll there is $630. Bought into Bet Online 3 weeks ago for $25 and my bankroll there is $35. Yes, I'm playing under my 100X limits because their minimum game is $1.50, but I've lost a lot of money over the years with online poker rooms disappearing on me, so I refuse to invest any more than the minimum. I also bought into Intertops 2 weeks ago for $25, and my balance there is $20. They only have turbo games, which to a degree diminishes skill and increases the luck factor. They have $.25 games so I'm adhering the 100X rule. The losses might just be due to variance. Time will tell.