How often do you use psychology in everyday life?

You first need to understand what psychology is. It's the science of how people think, respond to and understand their environment and how they interact with each other. Considering that humans are a social species, most of what they do is connected to other humans. So the obvious answer is that everyone uses psychology all the time.

Now, let's assume that you are referring to an active, willful use of psychology for a particular person, like myself. In my personal case, I'd have to say "all the time". I need to understand what people do, what they want to achieve, and what they want from me. It's basically the "lube" that allows people to work together better. So knowing more about why people do what they do and what they want and what will make them happier is pretty much the most important thing you can do.

So, that being said, I'd have to simply answer, "All the time."

First, you need to realize that psychology is the science of how people think, how they get along together, how society works in general, and, finally, how people "think they think". And how this all results in what they do and ultimately accomplish. So we all use some psychology all the time. Now, if you're referring to how often I personally, or anyone for that matter, use what they've learned about the science of psychology, I can say from personal experience that it's just about dozens of times a day. One reason is that I personally find it intriguing and entertaining and satisfying. The other is that it's useful to understand others and to understand yourself. The hardest part is using these scientific principles when your emotion gets in the way. It's easy to respond emotionally and immediately. It takes willpower to pause to reflect first to choose a wiser course of action based on knowing what your inner motivations are. So the bottom line answer is, "Lots".