Was it a Lenovo ThinkPad or another Lenovo product line?
I have a cheapest HP laptop with crappy plastic casing for ~5 years plugged in,
and its current battery capacity is only 96,2% from 100% after 5 years.
I've seen cheap laptops where the battery lasts but for the expensive ones (that say have a discrete GPU) seem to have good battery life for a few months.
Some of it might be that the big ones have to abuse the battery we had since the T.S.A. won't let you take a big laptop with an accordingly big battery on the plane.