Then I can focus on the fun stuff. 
same thing happened to me last year.I was originally booked with frontier who canceled our flight 3 months before our departure,booked with delta and then delta changed our flights to the point our layover flights were leaving 5 minutes after arriving.I called delta and was able to get nonstop flights at better times for no charge. stuff like this is the one downside to booking so far out.Since then my flights have been changed and layovers shortened to the point I called Delta, they rebooked me on non-stops at better times for no additional cost.
The last few years that has been right around 6-7 months before the trip. With SW, it tends to be right when fares are first released. On Delta, it can vary based on whether the plane is selling out or not.
As early as possible. I start looking @ flights at least 11 months out. Usually at the time the prices are pretty high. But I check everyday, at different times. Once I find a price that I like, I buy. In my experience, never did I find airfare cheaper @ 3 months out cheaper than further out. Seating is always limited/scarce and price reflects what’s left.I'm wondering when everyone books their flights? 3months in advance? earlier? When do you find the best deals?