A Stud starting hand on 3rd street with 3 cards of the same suit.
Dealt about 5% of the time. With nothing seen, it completes a flush 18% of the time (the usual figure). Example. After seeing the 5 other door cards at a 6-handed table, it's 22% if none of them is your suit, 11% if 3 are, and 6% if 5 are. If 3 or more of your suit are visible, fold unless you're stealing. It gains value with more players and cheaper cards to see.