It's so funny watching people having a cow over keeping log books, I'll wager most of us already do of some kind or other. Those involved in competition most surly do. Hydro probably does on his boats( which props on which hulls ect). I'll bet even Franklin logs his small bird flights ( because ,well, that what Navy does). I log the date of the maiden and tick off every flight of all my planes, usually on someplace like under the canopy or on a separate card in the transmitter case if no place on the plane. Even my little E-flite PT-17 has it's flights loged ( has 108) as of this weekend. Along the way if a servo dies or I bend a part I'll log that. My GS Yak I do a yearly I.R.A.N. replace clunk line ,ck. batt. condition and I log that. It's all on the underside of the canopy. It's the only way I can remember that stuff. When I first started in the hobby and servos far outlasted airframes I kept a log of what servo was in what plane and what condition. Don't do that anymore though I should. All that to say that logs are something we already do or should not because of the FAA but because who can remember this stuff anyway.