It is a commonly overlooked cycle requirement but as important as the gear or anti-e's. How could you explain a mid-myo abcess to your doc? Simple: you don't! Most use Cipro in case of abcess but the latest addition to the antibiotic line (Z-pak) has been used successfully by some and is just as easy to acquire.
Remember, not only dirty gear will abcess. If you inject too fast or too large of a volume it has the possibility to abcess even with the cleanest gear.
Don't wait until you have your first abcess to start looking...get your antibiotics BEFORE starting your cycle.