Condition: Good used condition, no major scratches or scuffs, some general light wear, battery "service recommended"

What does "service recommended" mean for the battery? Here is what Apple's own website says ...
Service Recommended: The battery's ability to hold charge is less than when it was new, or the battery isn't functioning normally. You can safely continue to use your Mac, but if your battery needs service or its lowered charging capacity is affecting your experience, get your battery evaluated at an Apple Store or Apple Authorized Service Provider, or contact Apple. 

I'm not aware of anything not functioning properly.