Question:

 Is it common for the battery to swell in old handsets?

Answer:

It is uncommon for batteries to swell in old handsets when used regularly under normal conditions. However, lithium-ion batteries may expand after prolonged periods of disuse. To prevent this issue, follow Samsung's recommendations for storing an unused handset:

Power off the device.

Use an official Samsung charger to charge the handset to 50-70%.

Every 3-6 months, recharge the handset even if it's not in use.

Store the handset in a cool, dry location to maintain battery performance.