If you have a pokemon that's about to be knocked out, check to see if it'll be worth retreating. If you keep retreating pokemon that aren't of use any more,  then you'll have a full bench of pokemon that are nearly knocked out. It is alright to retreat a pokemon that's still of some use. In fact, if a pokemon IS still going to be useful in the future, by all means retreat it! But like I was saying, If a pokemon has used up it's attack value, then it is best to let it take a fall.
 
 
Midget_Girl StarDreamer@titchmarsh.zzn.com