Why does my iPhone 5s run out of battery after 10 minutes of use?

I charge my iPhone 5s fully to 100%
The last few months after I take a few photos, make a few calls & look at Instagram the battery runs out.
Im waiting for the new iPhone to come out.
Do I need to replace my battery cause I don’t want to buy another phone close to the new iPhone release date.

Thank you
Why does my iPhone 5s run out of battery after 10 minutes of use?
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