The truth is that pruning the crape myrtles makes no real difference in the number or quality of bloom; you'll often see ancient crape myrtles when driving past old farmsteads around the South, blooming their hearts out in mid-summer, while nothing remains of the house except the firecplace and foundation. In this particular case, the trees at the driveway entrance have simply outgrown their space, and are no longer in scale to the surrounding landscape. The choice is to keep them in bounds through pruning, or replace them, which would be such a shame since they've just reached that point of having the truly magnificent exfoliating bark.
An appropriate caption for this one might be, "Really? You have fifteen of these to do? Really?" as the other Tim began tree number two today.
A particular difficulty with pruning Crape Myrtles is that their branches aren't especially strong, and are more brittle in the winter temperatures. Nick, the slightest of our group, gets the special job of climbing to the top of the extension ladder to do the finishing cleanup with pruners. Nick has vowed to become fatter before next year's assignments, so he can be at the base of the ladder.
Two almost done in this photo, only thirteen to go........(they really are the same height, just a bad camera angle....)