How often do you clean tank for fighting fish?

Provided the tank has a properly set up filter, substrata, growing plants, lights and is not overstocked there should only be the need to "clean it out" rarely (say after 12 months or so). There is however a need to regularly syphon the 'mulm' off the bottom and replace about 50% of the water weekly. If the tank is not set up as above then depending on how many fish are in it (to a max of 8inches) you will need to replace some water daily and at least 80% weekly.