When you’re betting your hands your goal is to out price the flush draws but still giving them a price so if they chose to call you they are making a mistake. For example for someone to be getting the correct price to call on a flush draw they need 4-1. I usually like to give them 3-1. I usually bet from 3/4 to a pot sized bet so they are making a mistake if they call you. If they are willing to call any price any time then if your read is that they are on a draw put it all in. This is how you make money in the long run by putting your money in when you’re a favorite. You might have lost the last 3 times when they hit they're flush but in the long run you will win more than you lose granted you are the favorite as long as they don’t have a open ended straight flush draw with over cards. As for dropping buy ins I don’t look at how many buy ins I drop I look at my state of mind and why I dropped the buy in. I'm pretty good at reading myself and you have to know when you’re playing bad or tilting that is the time to stop.