The 25% rule...
If you are up at a table, don't leave. It's a winning table and there is no telling how far your winnings can run. Instead, utilize the 25% rule.
If you are up $400 at that table and your winnings slip to only $300, you have lost 25% and it is time to leave.
On the other hand, if your $400 in winnings grows to $2,000 at that table, continue playing. If your winnings should slip to only $1500, you have lost 25% of your maximum winnings and it is time to leave the table.
NEVER leave a winning table yet ALWAYS protect your Bankroll.
Just reading through this---I also like this one!