Toothbrush Troubles

Do you have a favorite type of toothbrush? I can't say that I have one specific favorite, but I do have my preferences (soft bristles, thin handle). My husband also is particular about his tooth-cleaning apparatus. (However, he's more the medium bristles type.) I'm not a stickler for dental maintenance (I should be, though, after five years of braces), but I do like to follow the monthly replacement guideline.

Given these facts I've shared about myself, please help me answer this question: why is it that I can never find the same brand and style of toothbrush twice? I frequent the same two grocery stores. I look for a new toothbrush roughly once a month. Are toothbrushes like computers--in need of an updated version within 48 hours? Is it possible that the second you drive off the lot with your brand-spankin' new Reach brush that it decreases in its value and/or availability?

As I picked up my Aquafresh (light blue trim, soft bristles, flexible head) after another fruitless search for my husband's latest preferred brush, I wondered...are there antique toothbrush collectors in the world? If I actually watched Antiques Roadshow (I just can't get into it), would some middle-aged man appear with his father's circa 1949 toothbrush? My thoughts drifted back to my dilemma. Are there rare finds of toothbrushes for sale on eBay?

If anyone can tell me where I can get an Equaline, medium-bristled toothbrush in a July 2005 model, I'd appreciate it! Happy brushing!