I don't look at myself as a flipper but, I have sold lots of cards and memorabilia that I lost interest in.
Complete sets 1967 thru 1990
150+ early Baseball, football bobbers.
Obaks That played for Detroit
D310/D311 that played for Detroit.
My 1952 thru 1959 Detroit players
and many more.
Of course not because of someone's comments, just decided to go another route.
I'm sure others do this too.
I only collect 19th Century Detroit right now
Joe