As pointed out, it's a good idea to put higher octane fuel in the bike during winter when there may be longer periods of the bike being parked between rides. Helps keep the octane above minimum requirements as the octane does degrade over time.
If a bike will be in even longer periods of storage it is good to fill the tank as full as possible (helps prvent rust inside the tank) and to also add a fuel saver which will keep the octane from dropping much for up to about a year. These products are available at Walmart and the local auto parts store.
And if someone wants to really go all out they can add an octane booster to further ensure that the fuel is at full octane when the bike is eventually restarted.
Doing all this is another option to actually draining the entire fuel system as much as possible prior to even longer periods of storage.