Rule 16(b)(4) is deeply ingrained in the mind, body and soul of every DE lawyer. To modify the scheduling order, one must show good cause. Good cause, in turn, hinges upon the diligence of the movant.
More than 1,000 orders in DE patent cases analyze whether a party was diligent. Some have praised the herculean efforts of the parties (not a lot of those, honestly), while others cursed their lazy hides for daring hobble up the Courtroom steps (somewhat more common).
I have analyzed every single one to determine how often the Court found diligence.
I'm sorry that was a joke. We have a GoFundMe for an intern. Please donate if you would like that level of analysis. Instead I have looked at the last 10 such opinions and orders. Of those, a scant 3 found the movant diligent and granted the requested schedule extension, whilst 7 found the movant had delayed and denied the request.
Obviously this is a fact dependent inquiry, but it's something to consider the next time you move for an extension.