
I noticed that MSCD doesn’t contain the word ampersand. With this post, I aim to set that right for the sixth edition!
As Wikipedia tells us, “The ampersand, also known as the and sign, is the logogram &, representing the conjunction ‘and’. It originated as a ligature of the word et (Latin for ‘and’).”
I suggest that the only ampersands you use in a contract are those that appear in business (and law firm) names.
I recently saw this used as a contract title:

I’d use and instead of the ampersand, and I’d lose the blowhard’s initial capitals too! (For more about the latter, see this blog post.)
And I saw Amendment & Waiver used as a section heading. I’d use a semicolon instead (Amendment; Waiver), or I’d make them separate sections.
Why should you lose the ampersand? Because it’s too casual for regular prose. If you want to express the meaning and, use and.
So much for the ampersand!
