Quotations about:
    schedule

If it weren’t for the last minute, nothing would get done.

Rita Mae Brown (b. 1944) American author, playwright

Bingo (1988)
    (Source)

The phrase can actually be found prior to Brown's formulation (1, 2), but Brown appears to have been the first to popularize it, and it entered into much wider use after her.

Frequent variant: "If not for the last minute ...."