Refurbished with a new battery — battery life is essentially the same.

Basically the same, assuming Apple or a reputable shop did the replacement. A new battery is a new battery; it has the same cycle count and capacity as one in a brand-new MacBook Air.

The real difference is everything else. The SSD, the keyboard, the trackpad — those have some mileage. But for pure battery life in everyday use, you won’t tell them apart. The catch: a third-party replacement might not hold up as long or could lose calibration faster. Apple refurbished units come with the same warranty as new, so that’s the safest bet.

Don’t overthink it — if the battery is new, you’re good.