I disagree with this. You should start monitoring flights as soon as you have plans. This gives you a "baseline" cost.
If you see so.ethi g drastically lower, grab it. Doesn't matter how far away the flight is.
I've used this multiple times, and yes, sometimes booked at 10 months and prices never went cheaper. Another time I grabbed during a sale that lasted 36 hours 5 months out.
To answer the OP, no one can say what prices will do.