Just came across this standing requirement, from several orders by Judge Mark Goldsmith (E.D. Mich.):
The Court prohibits the use of excessive footnotes in briefs. A brief supporting a motion or response may not contain more than 30 lines of footnotes. A brief supporting a reply may not contain more than 15 lines of footnotes.
Of course, this is just one judge's formal position, but my sense is that many judges informally take a similar view. Here's my general view for briefs (not for articles), though again others may disagree (and much depends on what you know about the preferences of the particular judge, or the particular multi-member court):
