The Fortress

At the club level, knowledge of endgame 'fortresses' is a bit hit and miss. It is kind of like knowing how to mate with Knight and Bishop, in that the more you study it, the less likely it is to happen. To be fair, real examples of a position similar to the one given here are quite hard to find. I suspect this is because at the club level players don't know enough to go looking for them, while at the IM/GM level, both players do know enough, and therefore avoid them if they can.
However, this position did come from a real game, and there are a couple of lessons to be learned from it. Firstly, it came from a position where Black had forced White to play Ne2xf4 as there was a pawn on f4 threatening to win the knight with f3+. In doing so, Black had unwittingly given White more drawing chances than if the knight was left on the board for a bit longer. Secondly, White still has to find Kf1 here to hold the draw, which he did. Thirdly, once this happens, the only thing White has to watch for is the sequence Qxe3 fxe3 Kxe3 with the White king on the wrong square (eg e1).
For around 15 moves White seemed to have it all under control, until his concentration slipped. With the Black king on f4 and the rook attacked by the queen, White played Ke1 and quick as a flash Qxe3 hit the board. Realising it had all just gone wrong at this point, White gave his opponent a sheepish grin and resigned.