User blog:Fantasylover4life/Trying to understand the SPIKE rarity system

So recently, I have been getting confuzzling trades involving trading up/down from red/purple/blue longs. I normally get longs from trading den betas, so please excuse me if all this sounds weird and obvious to the more experienced folks xd. We know that den beta worth ISNT equivalent to spike worth.

So what would ppl consider acceptable to add,for example

--> if i wanted purple long and have a blue long. ( I have been getting blue long+ some black long wrists for my purple... and sometimes the infuriating blue long+1 den beta trade)

--> want red long and have purple. (havent tried this one much)

--> want red long and have blue (this one is all over the place, its almost as if some ppl consider a blue long 'decent' instead of 'good')

This is weird to me because ppl offer very different items when changing between 'good' long collars. And I am now wondering if somewhere there is a 'standard' and accepted value for what to trade, when trading up/down good long collars. Same could be said for short collars. I have looked around and asked ppl and have gotten the general idea. But could do with more opinions :)