How long before take off does the gate open?

Excuse me, could you please clarify for me the timing of the gate opening prior to the flight's departure? I'm trying to plan my arrival at the airport and ensure that I have ample time to make it through security and to my gate without any undue stress or rushing. Specifically, how many minutes or hours before the scheduled departure time does the gate for my flight typically open? This information would be greatly appreciated in helping me navigate the airport efficiently.