Seven years from a set of batteries is not bad going. Over 1,000 charge cycles but I started to notice bad performance and I got a warning they needed a service ??
Ok, not my boat batteries as they have been in two years now - need to check that ( was February 2019 so not quite 2 years )
This is the battery - or batteries as they are four linked together from my MacBook Pro late 2013. Still a fine machine I7 processor 16gb of Ram 500gb SSD and a lovely retina screen. So when the Macbook started shutting down unexpectedly I sought out Apple to see what they'd charge for a new battery - just short of three hundred quid !! I have other things to spend that on so I sought the sage advice of YouTube and found a fella replacing one with an OEM battery from IfixIt.
Eighty pounds DIY just don't puncture the thing that is stuck into the Macbook with industrial grade adhesive strips.
This is after removal, using adhesive remover and fishing line pulled under the batteries to separate the batteries from the case - slowly does it.