Battery Longevity / Replacement Question

Hi. I've owned this computer for 4 years. I bought it new, unused from Amazon. I almost always leave it plugged in to AC 100% of the time, just my home computer. Battery cycle count is only 94 but it's at 5120 mAH, or 89% of full strength per the Coconut Battery app. System Information also says it's "normal". Should I replace this battery as a safeguard given its age? Also, how should i treat the battery going forward? Should I use the computer occasionally on battery rather than AC and run the battery down?