When looking at Biblical text in terms of the Creation, people are often prone to detaching the first 6-10 chapters from the rest of the writing. This is then followed by various attempts to interpret what the text might be saying, without any reference to other portions of Genesis, or any of the other books.
In literary interpretation, this method is extremely flawed, as it ignores any following context or any continuity which may follow (Much like reading only the first chapter of a novel, then trying to interpret everything the chapter says, without referring to what is said later on in the book). This method of understanding a text applies to the Bible as well.
We have a simple question - According to the Bible, how long did the creation take?
Genesis states it happened in 7 24h days. This however has been argued against for various reasons. Therefore, to reach the answer, we need to look later on in the book to find if there are references back to the Creation's duration. One of the first references we can find is in Exodus, when God states the 10 Commandments. The 4th Commandment states:
"Remember the day of the holy Sabbath. Six days shall you labour, and do all your work; But the seventh day is the Shabbath of Yahuah Elohayka (or the Lord your God, depending on the version)............. For in six days Yahuah made the heavens and the earth, the sea, and all that in them is, and rested the seventh day; wherefore Yahuah blessed the day of Shabbath, and hallowed it."
This is a point in the texts where the Creator himself uses the duration of the Creation as justification for a regular cycle. This limits the possible interpretations which can be taken in regard to the duration of the 7 days. They cannot be 7 long periods of time, due to the logical extension which is made by the Creator later on.
I tried to keep it short... I'm sorry if the post became too long XD