What is "rare" :)

Reading Martins post ref rare and the trade forum in a sellers title, what do we consider "rare".

For example some one who does not own a 6105 could consider that to be a rare model but to guys who own 10 or 20 then it is not rare.

A bracelet end link if you havent got one and can not find one for love nor money could be considered "rare" but then other guys could have a box full.

Again a NOS (what is new old stock ) second hand could be considered rare and again a guy have a tin full so not rare to him but to some one who as looked for one for perhaps years it is rare.

So it goes on we all interpret statements differently.