I always aim to be at the airport 2 hours before the advertised gate close time, if not the flight departure time. I once nearly missed a flight home from not observing this rule (very long story that and one to be talked about in the pub with drinks!) so I am rather strict on that now. The stress of waiting in a long security queue is not worth it. My golden rule is better to be early than late.
Having come close to missing a flight once, and the stress it brought as I wasn't on my own, it's not worth chancing it. If my plane was due to take off at 0730, I'd aim to be arriving at the security area for 0530. Even if it was a 1930 flight, I'd aim to be there by no later than 1730. Even at London City or any other small airport, that rule would apply. If it was a trans-atlantic flight I'd aim to be there 3 hours before the flight was due to take off, which was Norwegian told us to do when I went to New York last year.
You may not get held up but why risk it?