I use an app called X-Privacy which can block specific permissions in other apps. For example, I see no reason why a calculator app needs access to my contacts

I use an app called X-Privacy which can block specific permissions in other apps. For example, I see no reason why a calculator app needs access to my contacts, phone, or microphone, and X-Privacy will let me disable permissions to those specific resources for the calculator app while still letting me use it. As a bonus, it'll also put in fake data in to these apps when needed, so the apps continue working, thinking they have access to my data but they don't. Something like this should be standard in every smartphone, but obviously phone OS makers don't value privacy enough, and even require root in order to allow you to do this.