Instead of writing my essay, I did a little research.

I get asked this a lot, so I'm happy to finally be able to provide the answer.

In Los Angeles County, restaurant inspections fall into two categories: routine and follow-up. Basically, routine inspections happen regardless of the restaurant grade, and they are random and without notice. Follow-up inspections-- to make sure that a violation which poses some threat to public safety has been resolved-- are scheduled visits. (There are other grey areas, like when a restaurant owner requests a re-inspection to improve his/her grade, but let's not get bogged down in the details.)

I would also like to direct your attention towards Environmental Health's Self-Inspection Checklist. Think of it as the home version of your favorite TV game show, except it's actually a way for you to inspect your own kitchen and I may begin to require it when I eat at friends' houses starting in 2006 (wow me during this generous three-week grace period!).

Helping you help me,
Ravi