Dinomike100 wrote on 05/27/06 at 21:37:43:

You dont need several hours for it. I taught it to kids at above basic level within the hour. The only thing is to repeat it in exercises every once in a while. Eg when players had finished their game too quick I would let them play these types of endgames against each other.

Why not play a computer once each day BNK v K and BBK v K reducing the allocated time as you become more proficient?
These endings are no doubt rare but getting to the point where executing them becomes second nature is good insurance.
You never know when hitting pay dirt might depend on either effecting the above mates or surviving them.

First of all learning to play the endgame certainly isn't a waste of time. I've been a trainer for quite a long time. I can remember the time when a pupil was required to learn the B+Kn endgame in order to pass an 'exam'. 

In my opinion a trainer can spend the time needed to teach this endgame more usefull.
For instance to teach severall basic rook endgame techniques.
For the B+Kn endgame it should be sufficient to show how B+Kn have to be posted in order to keep a K imprisoned, and how to mate a K that has been imprisioned in the appropriate courner. This should be sufficeint to show how B and Kn can work together. 
On the other hand the technique to get a K from the 'wrong' corner to the 'right' corner, is just a long trick, that has to be memorised. IMHO this does not add much to the understanding of practical endgame play.

I strongly disagree with the notion that learning basic endgame technique such as 2B+K vs K or N+B+K vs K is a waste of time.  Still, the argument apparently needs to be made again.

By learning these two basic endgames in particular, a player learns a great deal about how the minor pieces work together and how they don't.  When playing in simuls, I often finish one of my last games by promoting to B+N vs K to demonstrate how it works.  It also stimulates the "little grey cells" as Poirot called them.  (However, if they were actually grey it would mean that no blood was getting to them.  Oh well.)

Anyway,  the more technique a player knows, the better he or she will be.  The best examples are pawn endgames because they occur so frequently.  If a player knows what pawn endings are won or lost, that player can head to such positions before his or her opponent has even begun to calculate them!  Talk about a big advantage!   

If you learn the endgame thoroughly I can guarantee that you won't stay in the 1500 range for long.  The ability to calculate the endgames and to reach known winning/drawn positions alone will boost you out of the Class C range.