Hi greeko.... depending on whether they are single or double knotted, and the style you like to wear [brushed forward or back] visibility may not be an issue for you...... yes, bleaching knots will have a weakening-effect ....it`s a trade off. Some people like to order blonde hair at the front and then colour it themselves so they`re guaranteed no knot -visibility...however, my personal feeling on that is that the blonde hair had been entirely bleached in the factory seeing that most of this donor-hair is of Asian origin and is generally very dark, so in order to have ` blonde` hair , the entire hair shaft is bleached before being tied in onto the lace.... I reckon the only ``true`` or ` natural blonde hair, tends to be European /Scandinavian and this is too expensive for most of us..... Her assertion that bleaching will ` ruin` the hair is a bit of an exaggeration....certainly it can weaken it, but the factory usually don`t overdo it ...again ..it`s a trade-off..... thankfully I`ve never had premature shedding as a result of knots being bleached. Would be interested to hear your report on how the new system looks / feels when you get it !