We are traveling in mid June to mid July. We got tickets to Amsterdam from Victoria and from London to Victoria for $875. That was a month ago. When I saw the price I jumped, though ideally, we would have like to come in through Budapest or Prague and exit Amsterdam. We decided that at that price we will be happy with seeing Paris and London yet again. Actually, I'm always happy to see Paris and London again. Jumping was based on prices over the last five years. Given the likelihood of paying $1,100 to $1,200 for four, versus $875.
I'm willing to change plans a little. Look early and bite if you see something really low, otherwise wait for under $1,100 where you want to go. A couple years ago, we found round trip tickets from Seattle to London, round trip in the summer for about $925. Our plan had been in London, out Rome with Paris and Florence on the way, but prices changes our minds and we got a lovely train ride through the alps on our way back to London into the bargain.
How much prices matter to me depends on the number of people flying. The last three trips there have been four of us. In a year there will be just two as we are becoming empty nesters. Then, it will require a greater shift in prices to make up change our travel plans.
But, don't wait for a bargain for over five months. At some point, the news never gets better.