People make a common mistake of flipping meat too early when grilling, thinking it would prevent charring or overcooking the meat. Celebrity Chef Bobby Flay agrees, saying that overhandling meat is, in fact, the number one thing people get wrong when grilling.
According to experts (per Real Simple), the appropriate moment for flipping steaks comes when it "un-sticks" from the grate. Leonard Botello, pitmaster and owner of TRUTH BBQ in Texas, advises that for grilling steaks, "leave the steak face down for about four minutes and really let that crust build before you flip it to the other side."
The same goes with grilling burgers. Chef and sommelier at Cucina Testa Rossa in San Francisco, Laura Pauli, says, "let it cook for about 3-5 minutes (depending on size and level of doneness), then flip only once to finish cooking, never pressing down on the burger."