I watched the flights for this spring break from YYZ to MCO from the day they were released. There were Tango flights for about a month and then nothing. Sure, the Flex tickets fluctuated, but no deals like the Tango flights ever again throughout the year.
Of course, it makes a difference if you are going over a high demand week and if you're going midweek or on Fri/Sat. I'm about to get my Xmas flights for here in Canada this week, because those aren't going to get cheaper, either. But my summer travel, I'll buy in April.
I usually watch until it reaches a number I’m good with booking at. I never book st opening day out of Canada as I find there are usually many seat sales with WestJet or AC. I booked our April trip at the end of December, which is early for me. I am still looking at our connecting flights in the US (going to Phoenix first then onto Orlando), we are 6 weeks away and I expect to book in the next week or so.
A different strategy than travelling south, I travel often in Canada for work and rarely book more than 4 weeks out
We booked our flights for our October trip last month, which is far earlier than I expected. I found a crazy deal through google flights that was too good to pass up; just under $1500 CDN for the 5 of us from Vancouver to Orlando, with one layover in Chicago. The flights were at the perfect time of day, leaving Vancouver at 11am and arriving at 10pm (7pm for us, due to the time change). Leaving Orlando at 9:30 and arriving at 3:30. I couldn't have asked for anything more, especially for under $300/person. I saved $1000 compared to what I was planning on spending for flights!