Non-ethanol is usually quite safe for long periods and doesn't chew up carb internals. I'd say you're probably fine for at least a year if not longer. The issue with fuel sitting is in losing the light ends of the octane molecule, so you'll need fresh gas if it's really old. Non-ethanol gas stores rather well if kept in a cool, dark environment.
Fuel with ethanol is almost universally where people have issues with storage or letting it sit in carbs.