Kerosene will last pretty well for a few years. It depends on what you're going to be burning it in though. For example, my kerosene lamps have no trouble handling dirty, degraded decades old kerosene. But my kerosene heater and Alpaca cook stove are pickier about clean fresh kerosene. The old grungy stuff ruins their wicks in short order.
You can extend the life a very long time with PRI-D though. It's meant for diesel, but it works fine for kerosene. You can also retreat it several times for even longer storage.