Chance you will be dealt two cards of the same suit: 24%
Once you have
suited cards, chance that you will
flop two more of the same suit: 11%
When you have 4 cards of same suit, chance you will get
flush by
river: 39%
Generally, without getting too complicated, chasing flushes is only profitable when the opponent is betting less than 39% of the pot. Learn about
pot odds on the FTR main site.
You really just need experience to know when someone else is chasing a
flush. I
don't know any odds on it. If you think that someone is chasing a
flush and you have
TPGK always bet the pot at them to give them bad odds to
call.
May I also suggest Johnny that you should spend time reading the beginners section of FTR (and all other sections), starting with all the stickys, from front to
back and perhaps get yourself a good poker strategy book. It is a brilliant way to rapidly jumpstart your poker skills.
Check the main FTR page for book reviews.