I've been collecting for more than 5 years.  My 
primary collections have been Sailor Moon and 
Last Unicorn.  At one time I had several cel 
books of Sailor Moon with cels ranging from the 
low end to the high end.  Anyway, over the last 
year I've trimmed down my 'for keeps' collection 
to something I can live with.  I pulled out ever 
SM cel I had and put them on my living room 
floor.  I then picked up the cels I was instantly 
attracted to and put them in the celbook.  The 
rest I put in a pile.  Over about a week I looked 
through the celbook and the other pile.  Any cel 
I didn't 'miss'after a week went on the for sale 
block.  The rest went back into the celbook.  
Surprisingly enough, I'm extremely satisfied with 
the collection.  Now I'm MUCH more picky about 
any new additions to make sure it fits into the 
overall make up.  So my obsession is more 
contained.

On the other hand, I doubt my obsession for Last 
Unicorn cels will ever be sated.  But oh well ...