I play d'addario 10-46. Thx for the answer. Interesting. When I practice several hours everyday, especially picking exercise, or lot of funk songs, after 7-14 days pick becomes sharp like a razor blade and I can`t pick at the angle of 45° anymore because pick just slides too easy down the string. It gives no resistance anymore and i play less precise. I have read on the internet, some people waste a pick at one rehearsal. It happens to me on almost every "gig" at club. I give all wasted picks to my neighbour who plays so good that I call him Serbian John Mayer and he says: Very nice, NEW picks! He can play one pick at least 6 months, maybe a year. I also can play songs with wasted picks, but can`t practice serious exercises like x-pattern, ladder, picking on 6 strings and others from pbguitarstudio in a proper way - at angle of 45°. Yes, I ask for exact expiration date :) Or, how is it possible to play in a proper way with wasted pick?