Commercially-available 1x__ bikes usually have a "bash ring" on the outer position to prevent throwing the chain off the outside, and the better ones will have a "chain keeper" mounted to the seat tube near the bottom bracket to catch the chain if it drops to the inside. The best thing you can do without those gadgets is to use a SS-specific chainring (taller teeth) and to keep pedaling over bumps -- that keeps tension on the upper run of the chain so it can't fly off as easily.
To answer your other question, 50 posts.
