How to avoid having an iphone swelling battery?

I'm planning on buying an iPhone 4s but I kept seeing people saying that iPhone recently have problems with their batteries, such as a swelling battery and might cause an explosion
SO I want to ask how do I avoid having a swelling iPhone 4s battery?

A swelling battery can come from 3 things. 1 an internal short (manufacture defect ) 2 being left in direct sunlight (letting it sit on your car dash all day in the summer heat ) 3. The battery being completly discharged ( dead) and freezing ( the less of a charge a battery has the higher its freezing point )

No no, no such thing as swelling problem but 4S did have problem earlier with battery consumption but it was after the firmware update release from Apple, but after a weak and half, they fixed it…

Swelling of it, happens mostly due to non genuine parts, like a charger's unstable voltage or battery, itself, when it is not an Originally genuine one. And Explosion of batteries may only happen when you through them into fire.

So you are good to go for it

I've never heard of an iPhone battery swelling. Had an iPhone 4 for 2 years & no difference from the day I bought it to the day I sold it.

My friend just had to replace her iphone 4 battery do to swelling.