Should I keep it plug in to the mains when I listen to MP3 ?

When I'm in the office, I listen to MP3 using my Nokoa 6230. Should I
plug it into the mains and keep it charged or should I let the battery
drain when I listen to MP3 and then charge it at the end of the day.

Which option give me a longer overall battery life span ? Thanks.

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› See More: Should I keep it plug in to the mains when I listen to MP3 ?

When I'm in the office, I listen to MP3 using my Nokoa 6230. Should I
plug it into the mains and keep it charged or should I let the battery
drain when I listen to MP3 and then charge it at the end of the day.

Which option give me a longer overall battery life span ? Thanks.