The saws in my shop both have guards on them and I use them religiously. Sort of feels like driving without my seat belt if they aren't on. However, my jobsite saw has no guard, only because I bought it used and whoever owned it prior to me took it off and lost it, and I've been too cheap to buy one for it. But it scares the begeebers out of me every time I use it, so I think I need to pony up the money for the guard. In the meantime, it has my absolute undivided attention whenever I turn it on. Regardless of how careful you are, accidents can, and do, happen.
I think I'll order that guard today.