All the major tool companies use battery platforms that have been stable for much of the decade. I've used Dewalt 20v Max tools since 2011 and never broken one. Ego's yard tools were introduced in 2013, and the battery interface has not changed since. I have their mower, leaf blower, and two weed whackers, operating for over four years with zero problems. I haven't even had to replace any batteries.

Meanwhile, my neighbor's expensive new gas-powered mower has been in the shop twice in the past few years. When it does work it's loud and smells like shit.