I got 10 years and 175,000 miles out of my OEM '07 battery. I changed it last year "just because". Reserve capacity was down but it still started the bike reliably. Question is, "Do ya feel lucky?".
Are you often in places where a failed battery would be a big problem?
Do you carry a Lithium battery jump starter?
Do you at least carry booster cables?
Irrespective of number of miles or the number of times that the battery was abused (i.e. deep discharge, overcharge etc.), the 13 years age would be of some concern to me. I think I would certainly consider changing it but it might depend upon the answers to the questions I posed, above. Usually, there are warning signs that a battery is on its way out but a shorted cell or an "open" failure can happen very quickly.
Does the bike start easily after a week or more of inactivity (not on a tender)? (if no, it is a sign of high self-discharge rate - replace it)
If you kill the engine using the kill switch and leave the ignition (and headlights) on for five minutes, does it still start with authority? (if no, it is a sign of low reserve capacity)
If the above are OK, at least get the battery load tested by someone who knows what they are doing.
If you have a pass on these three items, you are probably safe for another year (but carry a jump starter, just in case).
Good luck.
