I want an easy way to track how much time I've spent on certain projects. I really just need a plug-in that tracks how long files have been open. I'm having trouble searching for one like that; does anyone know if this exists as a plug-in or even as a function of Photoshop (or Illustrator)? This would be very helpful for freelancers. Thanks.
Photoshop CC has the History Log option in Preferences > General
If all you care about are file open and close times, Sessions Only may work for you.
If a client wants to know what you did, you can go with options like Concise and Detailed.