Here are some threads which might be helpful for you:
*
guide for understanding rarities*
how much is this pet worth*
how much is this pet worth in C$*
the rares' list - there's a list of gaps on page 4
I've set up some examples for you.• two '17 uncommons = '16 uncommon, a '15 common, '14 very common or a '13 omg so common
• two '16 uncommons = '15 uncommon, a '14 common, a '13 very common or a '12 omg so common
etc.
• '17 uncommon = '16 common, '15 very common, '14 omg so common
• '16 uncommon = '15 common, '14 very common, ..
etc.
• '10 uncommon = two '11 uncommons, four '12 uncommons, eight '13 uncommons, 16 '14 uncommons, ..
• '11 uncommon = two '12 uncommons, four '13 uncommons, eight '14 uncommons, ..
etc.
You always multiply by two and when trading for pets from previous years, you have to divide by two.
(32 '16 uncommons = 16 '15 uncommons, eight '14 uncommons, etc.)
as for pets from same year: uncommon = two commons, four very commons or eight omg so commons
As for rares, two rares also add up to a rare from previous year. It's basically the same with multiplying and dividing (doesn't count for list pets).• '17 rare = '15 uncommon, '14 common, '13 very common or a '12 omg so common
• '16 rare = '14 uncommon, '13 common, '12 very common, ..
etc.
People usually value a rare at four uncommons from the same year:
• '17 rare = 4 '17 uncommons, 2 '16 uncommons or a '15 uncommon
• '16 rare = 4 '16 uncommons, two '15 uncommons or a '14 uncommon
etc.
• '14 rare = 4 '14 uncommons, eight '15 uncommons, 16 '16 uncommons or 32 '17 uncommons
etc.
• '12 rare = two '13 rares, four '14 rares, eight '15 rares, 16 '16 rares or 32 '17 rares
etc.
And the other way around, like:
• 32 '17 rares = '16 '16 rares, eight '15 rares, four '14 rares, two '13 rares or a '12 rare
etc.
Store pets value:'18 store pet = late '10 rare
17 store pet = mid '10 rare
'16 store pet = early '10 rare
'15 store pet = late '09 rare
'14 store pet = mid '09 rare
'13 store pet = early '09 rare
'12 store pet = two '09 rare
'11 store pet = two '09 rares + a '10 rare
Some store pets were released until next year. So for example, the corgi store pets were available from later 2013 to early '14, so they're worth an early-mid '09 rare.
I hope I have been a little helpful ^^
(fixed store pets value guide)