An Ounce of Prevention is worth a Pound of Cure.
1) Most importantly, take care with the zippers.
a) Periodically, clean them and lubricate them with bees wax applied at the corners or spray silicone spray on them more frequently.
There is a zipper lube product called ZippyCool that is made by the zipper manufacturer, YKK, if you want the factory approved lubricant. You can find it at this link www.sailrite.com/Zippy-Cool-Kit or on eBay.
Lubricating the zipper teeth, keeps the the closing mechanism, the Slider, running smoothly and avoids deforming it by having to pull harder and harder as the zipper teeth become dirtier and dirtier.
Failure of a zipper to join is caused by this action of bending the Slider.
b) Do not abrade, melt, crush, or otherwise destroy the zipper teeth.
Don't drag the zipper chain or rough surfaces like asphalt or roofing, lay your torch on the zippers, drop your pack or the like.
The rest of the pack is made of heavy duty nylon and it will last a long, long time as long as you don't cut it, melt it, dissolve it, or drag it down the road on your trailer hitch.
That's it.
