Sort:  

I guess you got one from the good batch haha.

I only enable mobile internet, wifi, GPS when I need to use them. Using CyanogenMod 13.
In reality... I maybe make 2 calls a day and rarely use any of the things mentioned above. Battery lasts about 5 hours if everything is enabled and your are actively using the phone. When left idle the battery can last a week. It's all about how often and for what you use your phone.

CM13 is great right. Had it installed on the S3 as well. Tbh who wants a phone that you can barely use? I ditched the S3 man :/ And yes i only enable mobile internet and GPS when I needed it. However wifi was always on.
Received the Galaxy J5 as a gift and because I couldnt afford to spend more money to get a new phone. The J5 lasts 1.5 days using mobile internet a lot and wifi is on all day :)