How early should I get to the airport is a great question. I wish I knew the answer.
A lot of people like to cut it as close as possible. Others like to give themselves plenty of time so they can still make their flight even if they run into a glitch – you are chosen to be the lucky random person for a personal pat down in security, nobody at the check in counter, an extra 1/2 hour to get to your gate because there’s US Customs preclearance (especially at many Canadian airports), your flight leaves early for some unknown reason, or oh, it’s a bus or a train ride and a mile walk to the gate. All of which have happened to me.