When is a "terms and conditions" and "privacy policy" page necessary for a blog ?

This is a good question I've found on quora. Follows my answer.

You can shake the hands to agree with someone about something, or you can write it down, to prevent problems.

It really depends on what you do on your blog, where your readers are located and how much your readers can do on your platform.

Then check if you are using plugin or embed from other web services: you could have some rights restricted and some duties enlarged.

Secondly if you blog for money, then talk with a consultant not for the terms of services, but to think about your business.