I just realised I hadn't informed the Authorities of my changed employment circumstances, then again the zairyu card only has space for residential addresses and now I can work in my desired profession (Nigerian street tout) without any restrictions, I guess there wouldn't be any point anyway. Anyone know anything to the contrary?
FWIW I see the zairyu card also has space on the back for a 在留期間更新等許可申請欄, which presumably will replace the stamp they used to put in the passport, so I guess that might be handy if one forgets to apply for an extension in a timely manner.