I played flat-wounds for my first 5 years. Then discovered super slinkys from a band member. I went with 9's for a while...easier on my fingers with cheap guitars. Went acoustic for 20 years and played D'Addario (D'Merle?) lights on a 1969 Brazilian rosewood D-28 that I sacrificed food money for in college...a great investment!...and changed them weekly. (Hulk Smash!) I loved them the 2nd day. 1st day? Too bright. After the second day, they'd go gradually downhill and usually time to change by the next week...or two. I played A LOT in those days...and only had one guitar, but it was really a good one...still have it. Now, I have 15 or so electrics and about as many tube combos. They all have D'Addario 10s. I bought a bulk pack of 50 sets. Other brands are fine too...no difference. I don't like 9s...Too floppy... and 11's don't seem to have the right amount of zing...or something. I even tried 10.5's. They didn't have the magic either...felt OK but sounded wrong to me. I just like 10s! Sometimes, I think something a little bigger would work for me, but the ones I've tried just don't have the sound. I'm so used to .010's now, my fingers know just what to do. ...Oh, and unlike many players I've talked to, new strings don't sound or work better for me on electric.