I can get over a years wear out of an 18' pole which i use 5 days a week. I try not to over tighten the clamps. If you do that it causes the fibreglass poles to wear out more quickly. You just want the clamp tight enough to clamp the pole so there is no lateral movement on the pole.
Vary the poles length in clamping can prolong the lifespan of the pole, What i mean by that is if you have an 18' pole dont allways pull the first pole all the way out and clamp it in the same place when you do an upstairs window, sometimes just pull it out 4' or 5'.
my poles usually go thin at their shortest length, ie my mini pole is used most often without extending the sections, but because i am giveing the glass a severe thrashing at times the clamp just wears out this section of pole, So it will grip the pole if I extended the pole were it as less wear. On the worn out section i wrap some insulating tape around the pole just once. It allows the clamp to slide over the tape but when i close the clamp it grips the pole.
Nel