Endgame study - how much time per exercise I've decided to give endgame study high priority, and I'm studying Dvoretsky's Endgame Manual, though also glancing around in other books. The issue is, that I'm finding Dvoretsky's exercises really, really difficult, and I can easily spend an hour or so on a single exercise and still miss something. This goes even relatively simple looking pawn endings.

I would like to know, from players who consider themselves as strong endgame players, if it sounds reasonable to indeed spend so much time per exercise? Or maybe, a more recommended course of action would be to spend 10-15 min on each exercises, look at the solution and try to internalize what the thought process should have been to get it right?
If you're an expert player (>2000 Elo) there is nothing wrong with taking your time on each exercise; you will get most of them eventually if you put in some serious effort.

However, if you're rated 1700-1900 Elo (or even lower) you will most likely fail on most exercises in the Dvoretsky book, even if you spend lots of time on them. In this case you could spend 10-15 minutes on an exercise, and if you feel like you haven't found the solution you can setup the position on a chess board and start moving the pieces around to see whether you can find the solution this way.

Dvoretsky's endgame manual is an excellent endgame book (arguably the best general endgame book out there), but it's aimed at players who are already quite strong. There are other great endgame books on the market that are accessible to players at a lower level; I'd recommend Silman's complete endgame course by IM Jeremy Silman, and 100 endgames you must know by GM Jesus de la Villa. Both of these are structured in a radically different way from Dvoretsky's book, but they are easier to follow and will give you more bang for your buck as a lower rated player. Dvoretsky's book can wait; it will still be there when you've gotten strong enough to take full advantage of it.