I have been running Anakee II tyres now for years and always changed them as they squared off, usually about 5/6000 miles running them at 32/36psi. The last ones I fitted I put 40 in the front and 46 in the rear and I am at 6500miles and no sign of squaring. There may be ever so slightly less contact surface but I am happy with the performance of the tyres at the higher pressures. It'll be the first time I've got two European trips out of one set of tyres.