i have never broke a chain and i have started to carry a chain tool on the saddle bags of both my bikes, i carry a few spare quick links in case a chain snaps but with out a tool i would be screwed for removing a broken one to fit the quick one.
last thing i want is to be over 20 miles from home and kick my ass for not having one when i need it since it is so small.
when i was a kid i seen my sisters bike chain snap, it was not good, just thankful while up the bing she wasnt been mad like me and my cousin and sat about.
right near the house going slow on the way back it snapped and she went head first
both my bikes have quick links on the chains as standard think their sram or used to be as im on my 3rd mountain bike one lol