brand new iPhone already declining after one month?

so i got a brand new iphone just four weeks ago, and i was very very adamant about preserving the battery life since my last one went bad VERY quickly... i was adamant about not talking on the phone so much.

i unexpectedly used my phone far more than i ever could have imagined, and in just four weeks i have already logged 60 HOURS of phone calls when the phone had 0 minutes when i checked on it's first day.

and i had my phone on all day yesterday, but didn't use it once for anything and the battery life went down NINE PERCENT and it was on 'low power'.

that sounds like my phone is already declining very quickly... what do you think?