Quoted from vid1900:If you buy a used car, the first thing you do is a synthetic oil change.
If you buy a used pin, the first thing you do is completely rebuild the flippers and bushings.
Not always, the guy I bought my GTO from was running 0-5wt synthetic, I changed it using 10-30 with ZDDP but it was too late he had already destroyed the engine.
Cost a helluva lot more than a flipper rebuild.