How many hands do you think it should take (on the average) to win 20 BI's at a specific level (i.e. 10NL, 25NL, etc)?

To be honest, I tend to get frustrated and doubt my abilities if I don't reach +20 BI's in around 20,000 hands. I then either make changes to my game and/or tilt, which in both cases negatively affects my winrate. Which is probably a big reason why I can't get past the micros.

Also at what point should I do some major leak finding? In other words could you please fill in the blanks:
"I've played _______ hands at xxNL, and I am currently break even (or worse). I need to get my ________ together because it is obvious that I'm not beating these current stakes.