How to keep track of your published posts?

Have you ever asked yourself that question? Because I am really lost at that point. I get ideas for posts every time. There's almost no day that I don't create a draft for a new article. But here's the thing: how do you avoid creating two similar posts on the same subject? I mean, now, when the number of my posts is over 300, how can I keep track of what I've written and what I haven't about?

I began researching the subject and realized that everything people ever written about was how to keep track of your post ideas and what plugin to use to do that.

But there's nothing about keeping track of your already published posts. Like when you publish an article on a specific subject and then, after a while, when you  totally forgotten you already written about it, how do you avoid on writing the same thing twice?

After a shorts discussion with a friend I was suggested to subscribe to my own blog so I could see the list with text synopsis. I should give it a try.

How about you? How do you keep track of your published posts?