I almost always wear mine when the motor is running; like wearing the seatbelt in your car, it's stupid not to do it. I do take it off when fishing for most of the reasons mentioned. I have kept it on when lakes have been total racetracks, but I usually fish during the week, so that's pretty rare. I always wear it in the canoe or kayak. I've only taken it off in the canoe once, fishing Lake Michigan in 98 degree weather. I ended up jumping in that day, vests aren't conducive to swimming.