If it's 1st, 2nd, 3rd, or 4th down, and the offense runs or passes, and at the end of the down they still have the ball and it will be 1st, 2nd, 3rd, or 4th down again, put 40 seconds on the clock and run it.
If anything else happens put 25 on and wait for the chop.
(I cannot take full credit for this.)