Of course, who would you consider normal?  :)

I personally don't go back to review a certain
scene because normally the cels/sketches I buy are
from series that I am currently watching or have
recently watched.

As for cels "sitting" in a site for a while, I am
normally hesitant to buy it because it means that
the price is probably too high or something could
be wrong with the cel (in some very rare
circumstances).  I sometimes just sit and wait for
a sale to buy them.  Unless it is something I have
been hunting for for a long time, I just can't
justify paying certain prices for it.