I'm always more concerned about getting my luggage checked in within the time-guidelines my airline recommends. Most international flights recommend 3 hours. I usually check one bag. If that weren't the case, I'd probably go ahead and arrive about 2.5 ahead of scheduled BOARDING (which is always about 30 minutes prior to the actual flight)
Some people would rather so me that extra hour on the beach, but at that point, really... what's an extra hour? If you haven't done everything you wanted by then, an hour won't help! Book another trip, haha !
I am a proponent of Club mobay but haven't found a huge benefit to the outbound security line, as yet. I travel [home] mostly on the last Saturday of April, which on occasion is the first Saturday of May. I have seen the line run the length of the departures hall, however, and would absolutely HATE getting stuck in that kind of line. Ive had both fast and slower lines at my airline counter. I think it's kind of hit or miss, aside from the more obviously busy travel dates. I have only traveled in April and June.
