Most people I deal with in this situation understand that they get the "friends and family" rate. Whatever that rate may be. And they also understand that the rate will and does change based upon their request and my current rates.
What I generally do is:
JobPrice = (cost + (rate- 20%)) + understanding that priority is low (to be done after other clients' work is complete or during downtime while waiting on proofs, etc.).
If they want top priority service, they pay my full rates. And I always provide pricing before any work is begun. That way if they think the price is too high, they can tell me not to bother.
With this basic structure, there's no need for me to keep track of any actual dollar figures I charge "friends and family". I merely run my current rate, whatever it is, through the formula.
With all this being said... true friends and family get free services from me. Chances are 99% of what is needed are not major projects and are often simple 1 hour (or less) projects for me. And because... well... they are important people to me and once you start introducing money, you start chipping away at those relationships. Just watch a few episodes of The People's Court to see relatives fighting over money. There's no need for me to charge anything for most of the stuff my family needs. I only charge when a business associated with a relative/friend wants my business services. I'd honestly rather turn down work for family than get into money squabbles with them.