The paragliders today are magnificent, technical and taut and that with few lines (except the monsurfaces !).
During their development, the designer and the test pilots very precisely adjusted the lines to obtain the desired performance, behavior and therefore certification.
Line length charts are accurate to mm !!!
After a few dozen flights already, it’s a bit like finding yourself with a car with slick tires, worn brake pads and very poorly tuned carburetion.
Use slows our gliders, bringing them closer to stall and can make take-off more difficult. It also alters the handling and all the characteristics that have been defined by the manufacturer, validated by the certification and chosen by the pilot !!!
An unmaintained canopy runs a great risk of no longer meeting the certification criteria !!!
However, periodic maintenance is an integral part of the certifications and its frequency is even indicated on the certification stickers affixed to any certified paraglider !