Surges

Hiya. I see a lot of posts with women worrying they've missed their LH surge and whether the tests are positive or nearly there. Please forgive my ignorance, but if you bd when you suspect the surge and the surge happens the next day, is it a big deal? Can you not just bd the next day? Glow is forever throwing (the same) insights at me "Most couples who conceive have sex every day of their fertile window". I'm confused and would appreciate some insight :)