Every class. kata -> bunkai -> kumite (of various types from punching and kicking to rolling about on the floor.) Obviously with lower grades, simpler and arguably more effective techniques. I think one of the aspects is to teach the independant analysis of kata. A lot of clubs have broken the link between kata and kumite, which is a shame, it devalues the art. If you think you don't do enough bunkai, or don't link it to kumite there's a book you should read. Actually, it's a book every karateka should read. Bunkai Jutsu: Ian Abernethy