40 years of catching flights about once every 14 days, on average, has taught me that to be in a traffic jam in a car, bus or taxi, or on a delayed connecting flight, or in a delayed train with an hour in hand is totally stress-free. So I always leave for the airport with an hour or early, if I haven't stayed overnight within a mile or so of it.
It's Risk Assessment time:-
Leaving without allowing for delays - risk is total loss of flight, return home, buy new ticket perhaps, lose money, trip and meetings disrupted.
Leaving with allowance for delays - risk is 60 minutes extra in departure lounge and cost of extra coffee. Possible risk of additional shopping cost with Mrs C if she has come too, but not if one obtains her card and hides it........... "Oh dear, did you leave it behind?".
It's a no-brainer. But she still hates it and invariably complains if we arrive too early. This is not changed but exacerbated by me reminding her that travelling on her own she has missed several flights.