I replaced my stock battery in this 05 AccentGt the first summer. It was a 450CCA and simply inadequate to the task. The AC would cycle on and off and the headlights would flicker with the cycles. The windows were slow to go up and down, and the heater didn't blow as hard, all indicating to em that there was no reserve and the alternator was doing ALL the work. I replaced it with the biggest Duralast Gold (1000CA, 900CCA) to a great effect. The headlights lost the flicker, the cabin air fan was much breezier and the power windows positively raced up and down the tracks. Bad part was, that thing was so big it impinged on the hood-rod clip. So, sold it to a buddy with a larger Nissan 6 months later and bought a Costo/Kirkland that's 900CA-800/CCA and small enough to fit the tray, but still neary twice the capacity as the stocker. At 60.00 a great buy.
Point is, so WHAT if the old battery cranks? If the thing is running even 1/3 down from it's original capacity at 4 years (or three or even two), why not save the load on the alternator, the accessories and the starter? Seems like such a false economy to me when you consider the ramifications of a faulty (if slightly) $60.00 battery. Especially when you consider one tow can cost you $150.00 in addition to the sheer fun of a breakdown to begin with. Pay em now or pay em later..