Vodka can last for 10 years or longer as long as the Vodka has remained sealed and hasn't been opened.
Once you open the bottle of Vodka it should still last up to 10 years as long as you keep it sealed when not drinking it.
However overtime the Vodka evaporates and it loses it's flavor so the older the Vodka gets once opened the less taste it has and it won't be as enjoyable.
Once you open a bottle of Vodka it's best to drink it up within a year or 3 years at most.
However the Vodka is still safe to drink for many years.
But if you want the best taste and enjoyment from the Vodka drink it within a year or 2.