This is kind of a "stupid" question. Different airports have different suggested times to be at the airport. Some DIS live 5 minutes from the airport. Others are driving hours to their nearest airport, or to the nearest airport which offered good fares. A person driving from Canada to take a flight from Buffalo is likely to arrive at the airport very early if they properly allowed enough extra time for traffic and customs and said extra time wasn't required.
A better question might be how many DIS allow more time then suggested by the airport or how many posters think they know more and plan on arriving at the airport with less time to spare then recommended by the airport.
I plan on getting to the airport at least as early as suggested by the airport. Typically 90-120 minutes.
Some people think they can get to small, local airports, close to flight time. A small airport may only have one, or two, security lines. At least one small airline shuts down (or used to shut down) baggage checkin something like an hour (more?) before the flight. The employee who checks luggage closes the checkin desk and becomes the gate attendant.
People need to find out the deadline to check luggage and the suggested arrival time at the airport.
Flights are frequently overbooked. Getting to the gate early might make it easier to accept a bump and make it harder for the airline to involuntarily bump you.