you can be a master plumber in 12 weeks,ie you are able to design and install hot and cold water systems all to correct sizes and regulations,same with central heating,gas work ditto,soil stacks,waste pipework,including gravity vacum double containment all to correct falls ,drains all to correct falls sizes and regs,soft solder, braise,copper work,lead roof work,zink and copper roofwork,solar thermal to all relevant regs and standerds,unvented cylinders,heat pumps ditto,be able to solve problems in existing water heating waste systems, it goes on !! i wish i had known all this when i first got into plumbing,all these courses are the bottom rung of the ladder .