The Already/Yet Trick

Two small words make present perfect easy: "already" and "yet." "I've already sent the email" means it is done, no reminder needed. "Have you finished the report yet?" means I am expecting it soon. If your sentence naturally wants either word, present perfect is almost certainly right. And do not overthink it: in casual American speech, "Did you eat yet?" is extremely common, even though the textbook form is the present perfect "Have you eaten yet?"