A timely topic - mine snapped this morning in bumper to bumper traffic - at the lever end. It's done 80,000kms so I'm not surprised, since I commute 100kms a day in traffic.
Keeping it lubed was the reason it lasted so long, I've seen others snap way earlier.
If it does snap you can get moving, just pull the lever to the bar, select first and hit the starter. It's a jerky old start, but you can get going and get to a shop or home to replace it, which is also a very easy job. WARNING - don't start your bike off on the starter too much, or often, I think you know why
Mick