When does the time window start for the term “due”?

Question

Say something (a bill, a task request) has a deadline of May 1st. It's pretty clear that on May 2nd, it's overdue. What's less clear, and is leading to some arguments where I work, is: at what point is it "due"? As soon as it's assigned/generated? Two weeks before the deadline? Midnight on April 30th?

Edit: to clarify, the debate centers around when is it correct to start using the term "due". We've been using it to label tasks about 2 weeks to a month before the due date, and some people are saying that that is misleading, because those tasks are only "available" that early, but aren't due until... well, some nebulous time closer to the due date. (Which leaves the rest of us wondering why the word "overdue" bothers to exist.)

Answer 1

Based on your revised question...

Generally, one doesn't refer to a task as being "due" without including a date. There are several statuses one might use for a task ("planned","in progress","complete","overdue"), but "due" isn't generally one of them. Instead, one refers to a task as being "due on March 1" meaning it should be completed by March 1.

For the "this task is due two weeks out" status, I would use "due soon" rather than "due."

Answer 2

The multiple definitions of "due" make several of you right.

Merriam-Webster Online has as its first definition "owed or owing." So as soon as the service is rendered, payment is "due."

The fifth definition is "having reached the date at which payment is required." Under that definition, the bill becomes "due" on May 1. (I believe that general practice is to consider the payment "overdue" if it has not been received by close of business on the date shown as the "due date".)