Equipment for sport climbing
The climbing system can be thought of as a series of links that connect the lead climber - via harness, rope, knots, runners and belay device - to a partner or belayer.
How It works
During a fall, force is experienced at every link in the chain
Each link must be intact and secure for the system to withstand a high impact fall. During a fall, force is experienced at every link in the chain. If there is a significant weakness at any one of these links there could be a failure with serious consequences.
In other words, there is no point in having brand new equipment right from the harness to karabiners and rope if you then clip an old, damaged or worn-out piece of 'tat' as your only piece of gear on a hard pitch - that's asking for trouble. Every link in the whole system must be reliable - your safety is depending on it.