Battery reduction in performance

[chaos3714]

My Galaxy S9 which I use as a backup gets a notification saying that my battery is deteriorated, despite getting my battery replaced and having pretty good usages?

Anyone know why I get this notification?

This usage seems pretty good for a phone this old

[inspired_chef1975]

Leaving the mobile phone inactive for a long time can lead to unstable performance or even the inability to power on. This is because when the phone is idle for too long, the battery's energy is depleted, which can impact the battery's lifespan.