I’ve searched a dozen contracts on my computer, and another dozen on EDGAR, without finding the word very.
That might seem odd, given that very is such a basic word. So basic, in fact, that Lexis won’t allow you to include it in a search.
But as a measure of magnitude, for contract purposes very is essentially unusable—the reader has no way of knowing where very falls on the spectrum from nothing to everything. The limitations of very bring to mind the unanswerable question “How long is a piece of string?”
The same applies to extremely. It occurs in contracts, but in a context—language of declaration—where it’s unlikely that anyone is going to fight over degrees of magnitude. Here are two examples from EDGAR:
The Purchasers acknowledge that the final resolution of all litigation, including the Qualcomm Dispute, is subject to many factors and, accordingly, is extremely speculative in nature, regardless of the relative positions and merits of each party’s claims or causes of action in such litigation.
Lessor and Lessee hereby acknowledge and agree that would be impractical and/or extremely difficult to fix or establish the actual damage sustained by Lessor as a result of such default by Lessee … .
To modify adjectives to indicate magnitude, a word has to be more informative than very or extremely if it’s to be of any use for purposes of contract drafting.
I suggest that you have two choices: significantly and materially, with significantly referring to a level of significance that’s important enough to merit attention and materially referring to a level of significance that would have affected a reasonable person’s decision. If I wanted to convey either meaning, I’d use significantly or materially, as applicable, as a defined term. For more on that, see MSCD chapter 8.