Short answer
Draft quality guides from the brewing industry commonly recommend cleaning beer lines with a line-cleaning chemical about every two weeks, with a periodic acid cleaning and regular disassembly of faucets and couplers. Dirty lines build up yeast, bacteria and beer stone, which cause off-flavours, cloudy beer and excess foam.
Many bars contract line cleaning to a service; others train staff to do it. Either way, keep a dated log of each cleaning.
Kegerators and short-draw systems need the same care as long-draw systems. The lines are shorter, not cleaner.
Check the beer dispenser's manual for the cleaning fittings it takes, and use a cleaner made for beer lines rather than a general kitchen sanitizer.
Updated · By Norpex