My day 1 Switch battery was definitely significantly degraded when I did a DIY battery swap a couple of years back.

Battery longevity varies based on usage patterns and likely other factors (temperature?), but it's normal to notice a significant reduction in capacity within 4-5 years.

And the amount of adhesive holding the old battery in made replacing it an unnecessarily hard and actually dangerous (risk of battery fire due to physical damage) process.

EU also forced Nintendo to provide lifetime free repairs on drifty joycons since Nintendo chooses not to address the issue.

https://www.euroconsumers.org/game-over-for-faulty-nintendo-...