Life saver poll to see if we bother !! for me : Not once that I can remember, I still do them though.
The first time out when i passed my test i took my dads bike up the road and started indicating to turn into a lay-by to turn around. I came to a stop and waited for a car to pass the other way. I was about to pull across the road into the lay-by, done a life saver and a car flew past me. If i didn't check and pulled across the road id have been a goner
I tend to do it a lot, I go out with a group of guys and its generally quite fast throughout the day, roundabouts are a must also, people around here tend to play Russian roulette, I've lost count the amount of times someone has tried cutting up the inside, it would appear lane discipline doesn’t matter while negotiating a roundabout.
Leaning forward on my blade, looking behind is never easy, I always life saver but have to say I can't see much and would'nt know if it has saved my life or not? That said its a good habit to maintain and I always will take a look.
Being an ex instructor i've been programed to do life savers and do them without thinking about it but.... I can honestly say they've not saved my life.