I slapped these on my fretless last night for the first time, but didn't have time to play the bass until this afternoon and WOW! I love these strings. They sound like roundwounds that have lost their zing after a month or so, and for me, that's a great thing. They're the perfect amount of brightness for me. I am a little curious though as to how often others usually change these strings? For what it's worth, I bought the light set, and play approximately 1-2 hours a day.