Still on my original battery on my 08 as well.
I too have cleaned the connection to frame or atleast checked it whenever I have had the fairings off. I remove the battery and bring it in the house each winter, typically thats about 4 months. I charge it one or two times during that period for 30 minutes or so on a 4 amp trickle down charger. Most every bike I have owned has seen atleast 5 or 6 years out of the battery, with a few of them making it past 10 years.
I would check the connections, fully chrage the battery and then see how it reacts to starting etc. You can load test it after getting it fully charged but the draw isn't like a car so don't expect it to have hundreds of CCA