I have always been a proponent of when in doubt, change it out. That said, I started this whole Spyder adventure in Alaska. Forty miles away from the big city and you are stuck, stuck, stuck if your battery goes.
Unfortunately, they do tend to go with little to no warning. For the winter sleep, (usually Nov - Apr), I would put the batteries on a Battery Tender Jr. (after a final long ride to charge the unit). I did not start them up during the layover. Come spring wake up, they always fired up to life on the first try. Fast forward to Arkansas...no winter lay up. No battery tenders, since they are being driven most every day.
My usual advice is to change the battery out at three years, whether needed or not. I am coming up on three years on the 2014...so will see how it goes this Spring. I need to make the decision to keep it or move on to another for Linda.
We are not in Alaska, but drive a lot of mostly deserted country roads. I don't want a battery failure miles from help. :bbq: