October last year I was at Tyagarah (Byron Bay) and filled up with mogas (unleaded 91 octane) for a 80HP Rotax.
10 hours later, my fuel filter had blocked up. I was fortunate in being only about 3 miles and 1200ft AGL from our airfield, able to restart and limped back to our airfield.
I insist that the guys at our airfield practice simulated engine failures regularly.
Number one priority being to get your best glide before thinking of anything else.
Factory specs of my aircraft: GR 6:1 and I teach 12:1
Almost all of us have a GPS which will give glide ratio, and it is easy enough at a safe height to find the best GR for the aircraft flown.