Condition-grading criteria for HP calcs?

[rprosperi]

There used to be an article on eBay, which has since been either removed or perhaps moved to a new address, which had a fairly good introductory section about HP calculators, which models were more collectable and why, quality ratings, etc. The article was titled "The HP vintage pocket calculator's 2008 buyer's guide 2 eBay" but it was still there until about 2 years ago, the last time I recall seeing it.

I don't know if this is the one you recall, but the odds are good.