Should I replace my iPhone battery?

My dad gave me an iPhone 4 and he used it for 3 years or something. It has gone through over 430 cycles and it holds approximately 75% of charge compared to the original one. It barely lasts a day and I'm thinking about changing it. Is it a good idea or should I wait a bit more?

If you can use it by charging it each night, I'd just keep it till the charge no longer holds all day.

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