My Fugi gun has a very nice fine strainer that slips onto the suction tube. I have looked at it and said to myself "that looks fine enough". And although I have had junk on it when finished spraying a pot it seemed to have done what it is supposed to do. Most instruction sheets for spraying say to strain the finish prior to use but is that really needed or are they merely covering their behinds? What criteria do you use as to when to strain or not?