There are many different kinds of endgames.

When I was starting, I was told that I needed to master the King + Bishop + Knight vs. King endgame with the aim to deliver mate within 50 moves.

If you’re familiar with this endgame, you would know that this is a tough one to master.

The endgame played perfectly needs 30-40 moves to execute and a single wrong move can make can set you back enough moves to call it a draw.

Later on, I was puzzled about how rare this endgame is.

I have played thousands of games by now and I have NEVER seen this particular endgame.

Something similar can be claimed for another famous endgame: King + Queen vs. King + Rook.

I have only seen it twice in my own games.

It was much later that I stumbled upon the following table from Wikipedia:

As you can see, the endgames I mentioned are indeed quite rare.

It is much more productive to spend your time learning how to play more common endgames, like Rook endgames.