Moving Up

[hamstacker]

I have been playing poker for several years with increasing seriousness. Last year I started playing on line. Over that year or so I have been concentrating on tournament play, playing small stakes SNG and MTT tournaments (generally $20 buy in or less). I also played cash games but tournament play probably accounted for 75% of my play. Since August I have been playing more and more cash games. I started a couple of new accounts and have been multi-tabling $.25 PL/NL Hold'em tables in an attempt to earn deposit bonuses. I think I have these games beat and would like to move up. Here are my questions (I apologize if these issues have been beaten to death).

1. How do you know when you are ready to move up?

2. I would like to move up by contiuing to play two $.25 pl/nl tables and adding two $.50 pl/nl tables. Is this advisable or should I only play one limit at a time?

3. I know that the suggested bankroll is 20x the buy-in. Is this 20x the MAX buy-in or just 20x the amount you actually buy in (E.g., if I play $1 NL, $100 max buy-in, on line and buy in for only $50 is a bankroll of $1,000 ok)? Is the 20x figure an absolute minimum? Is there a better number? Should it be a bit higher when you are entering a new limit?

Thank you in advance for you assistance!