The petroleum industry considers that fresh petrol can be stored in a sealed metal containment for up to six months.
It can reach storage periods of 12 months if in an optimum sealed, low temp, low temp fluctuating environment. Degradation begins the moment the seal is opened.
The petroleum industry manufacture and distribution is based on two slightly varying "rule of thumbs"
One being that there is a loss of 1 RON per month after the point of manufacture
Secondly it is assumed that most pump available petrols are consumed within a two month period.
Obviously one can add a bit of varying give and take to the above.
The Australian standard at the point of retail pump sale is rated at 91RON for regular unleaded and 98RON for premium.
But in actual fact they are manufactured at 93 and 100 respectively, because of the two "rule of thumbs"
Cars, bikes service stations, etc have vented tanks always allowing RON "gas off".
Underground Service station tanks lose less RON/period than the vented tanks on bikes.
So if it is tuned right to edge of your fuel selection (bumped up compression/ignition) and it is hard to start after sitting for a while?
And say you don't notice the pinging?? It will be OK if your wallet and frown are on standby.