phone - no
tablet - yes
tablet lasts long enough with it on, and the BT keyboard not needing that extra step to be useful is nice. with my phone, i don't use often enough in situations where BT would be useful (read: driving) where it's a hassle to toggle it when i do need it. of course, if i'm going to be driving, and i KNOW i'm going to get a call soon, i'll flip it on and connect the ear piece, but that's just good sense. now, if i could get a decent pair of inexpensive BT headphones, we might be having another discussion entirely.