ok..For experienced flyers I would suggest Liros lines. Available in 40(yellow) and 60(blue) Dan(for stunt kites).Very quality lines.Better than Protec. Have no chance to compared with Laser Pro.Longlasting, durable.Minus: price(expensive). I have sets of 40m,35m and 30m. I guess 35m would be the best choice for most big kites( 2,4m and up).
and yes.I have changed my line sets every year(into new ones, no matter how much they worn out).This is important for good performance.
Smooth winds and fairly skies