Two pages.
Frankly, if the value of my life is so low that they can't be arsed to read 31 years contracted to two pages, I don't want to work for them.
Nearly but no. You're correct in that it's most definitely the genitive case. However it is specifically the Saxon Genitive where the possession is formed by means of the clitic
'sWould you refer to "
one year experience"? No - because it doesn't make any sense without the genitive.
In the genitive, the phrase "
one year" is a noun phrase i.e. it acts as one singular noun. Just as you'd write "
Jon's laptop", you write "
one year's experience".
So to take that further, the phrase "
two years" is a noun phrase i.e. it acts as one plural noun. Just as you'd write "
the brothers' feud", you write "
two years' experience".
It's "
one year's experience" and "
two years' experience".