We all know that WTS likes to distance itself from the Young Earth Creationists, who believe in the literal 6-day creation.
So are we supposed to be something fundamentally different from the YECs? Not so much...
I did some research some time ago about what the society believes abouth the length of the creative days. This is what I found:
Publications written in the 60's and 70's: the creative days are 7,000 years each. (with regards to geological time, this is about the same as 24 hours; no big difference to YECs)
In the 80's and 90's this appears instead: The creative days conist of thousands of years each. (how many thousands? Tens? Hundreds? Millions?)
However, in a 1987 Questions from Readers, the "7,000 length" view is repeated again (for the last time).
In the 00's, this changes to: The creative days consist of long periods of time. (right. Very specific!) In recent publications, you'll see the "thousands" word has been dropped off completely.
And the best for the last: the Life (lf) brochure (2010) in p.23,24 has a graph depicting a soccer field. This represents the 4.5 billion years of Earth's history. A line is drawn at 1/8 the length of the field, representing the Cambrian explosion, which represents supposedly the creation of animals (hilarious, but our point is the length of the days). So: 1/8 of 4.5 Bya = 562.5 Mya ==> So, the creative days took place over 500 M years ago, says the Watchtower. Now, that's a step forward. But if the creative days last so long, then what about the 7th day? When was Adam created? If all days have equal length, when will the Millenium begin? In some million years??? You see the whole 7 days theology breaks down.
One good point is that the WTS seems to be getting closer and closer to scientific facts as decades pass by, albeit in a giant turtle speed. Maybe in some future generation it will endorse theistic evolution, who knows.