Mark,
Deep breath - it's not that bad. Missing all of the logs means a 10-20% hit on price because the first annual is going to take a long time to check all ADs. Missing a portion of the logs can affect price, but that's dependent on the time covered by the omission and how long ago that time was. In 1988 I bought a 1973 Cardinal that had been stolen a few years after new-the owner had kept the logs in the airplane (bloody moron). The airplane was recovered by the logs weren't. I knew the guys who owned the airplane at the time they decided to sell it, So, about four years of the logs were missing on an airplane that was 15 years old. A pretty good-sized percentage. I'd flown it and knew the condition even though one of the owners had gone nuts and locked the airplane in a hangar - took a year to get a court order to get it released and sold. The sellers also agreed to pay for an annual at a place I selected and pay for all squawks to be worked off.
I flew it for over 1,000 hours before deciding it was time to sell because I'd moved to Michigan and was getting bad heebie jeebies flying single engine over Lake Michigan. A couple of people who called me ended the conversation when I confirmed that it did not have full logs. They were a small minority. Within a couple of months in a slow market I'd sold it for the asking price. (Bought into a twin and discovered that I really couldn't afford that and got out of it after a fairly short time and then bought into a 150 - which I loved.)
