It is worth keeping in mind that a line from a worn lineset can break at any time during the opening or flight of your canopy, so don't assume if it made it through the opening it can't break during your final turn in to land.
They can and they do, particularly on high performance canopies where the additional centrifugal forces during a turn load the lines up. Don't just ignore your lines for the first couple of hundred jumps "because they're new!" Lines, especially small diameter HMA and Vectran, are harshly affected by environmental conditions. Sand, salt and dust can speed up the wear considerably, to the point that we occasional hear of line sets that have had to be replaced after just 200 or 300 jumps.
Try to develop the habit of giving your lines a quick once-over every time you pack, or if you use a packer you can spend a few seconds checking them while you're walking back from the landing area. After all, you are usually carrying your lines in your hand anyway. If you aren't sure, ask someone who understands line wear and how to check the canopy trim. It takes less time than the average pack job and could save your life.
Most line wear on a canopy is caused by both handling when stowing - packing, un-stowing during opening, and by friction from the slider. As the outside and centre lines have more contact with the slider during opening and flight, they tend to suffer more wear and tear than the rest of the line set.
Therefore the areas to pay the most attention to when inspecting your lines, are the points where the slider spends the most time while in use. Even if you always pull your slider down your risers, it will spend some time every jump flapping about right on top of the links. People using hard links should also be using slider bumpers but it still pays to push the bumpers down and check the lines just above the connector links for wear or damage to the line loops.
This problem with wear can also occur with soft links. In general the chance of excessive wear to the area where the softlink goes through the line loop is more pronounced when using HMA or small diameter Vectran simply because slider bumpers are rarely used.
On a regular basis we see line sets that at first glance look like they're in great condition, but the outside lines on the softlinks have been nearly worn through by the slider grommets. A similar thing can happen to the lines up at the canopy. Snivelling, slow opening canopies can show wear up by the slider stops. So keep an eye on these areas also.
As for the rest of the line set, when the slightly fuzzy look starts to become a slightly frayed look, it's time to reline. The fuzzy look occurs when the very fine microfibres that make up the strands start to break. This is fine... up to a point. Since there are only 12 strands that make up a line and carry the the load, a broken strand is a bad thing, especially on small diameter line which doesn't have much reserve strength to begin with.
If you are using an RDS on a regular basis, it pays to be extra vigilant. RDS rings cause rapid wear and we recommend checking your lines twice as often no matter how many jumps on the line set. When it comes to your lines, regular checks are key, as is taking care not to walk on them, drag them about the ground or slam them in the door of your car when you chuck it in the back seat unpacked at the end of the day.
We recommend taking the time to untwist your brake-lines regularly as this will help extend the life-span of your lineset. Watch this video here for how to do this.
Respect your lines, they are part of the life saving equipment you have spent all your hard earned beer tokens on.