Ratings: Date of rating

You can do this by exporting your ratings. Click on the triple dots and you will get an option to export your listings. It comes as a CSV which is viewable in something like Excel.

Edit: You can do this through the main website. I'm not sure you can do it on the app. I don't have the app to try.

Very compelling feature!
In fact, one of the most annoying things I find in IMDb is that I can see my rating but have no clue when I watched it and how long ago it was, cuz I hate watching same movie twice unless it was really long ago and I don't remember it anymore.
My suggestion to IMDb would be then, that if the user hovers over the rating of a movie, a little pop-up should discover the rating date(s), or how long ago it was.

Note @Adrian, that CSV is obviously not the right choice to dig into and discover the date when you're just exploring what to watch next.

P.S. I'm using the web app.

I think the problem would be solved just by adding another feature in the app under the Sort by, so you can sort it by the Date Rated, although I think it would be great to see every time you've rated something so far if for example your rating of a movie changed multiple times but that's the ideal approach, I could go with the first one easily.