Really, how many mic preamps should a sane home studio owner have?

Technically I have, 12 in my Soundcraft mixer, a Studio Projects VTB 1, a JoeMeek TwinQ, a Universal Audio 170 Twinfinity and ultimately an Avalon 737.  But yet, I catch myself scanning Craigslist and ebay trying to find the "good deal" on an ART Pro MPA or a UA 610 or a Golden Age Preamp.
There is no way that I would be lacking a pre amp in any realistic situation.  Is this silly or what?