Why a quarter
A year is too long to hold a team's attention, and a month is too short for meaningful work. A quarter is long enough to finish something real and short enough to correct course before it is too late.
Set a few commitments
At the start of the quarter, the leadership team agrees a short list of commitments that move the plan forward. Each one has a single owner, a clear finish line and a measure. If a commitment cannot be finished in the quarter, break it into a part that can.
Check in every fortnight
A short meeting where each owner says, for each commitment, whether it is on track, at risk or off track, and what help they need. No long updates. Problems surface early because the meeting expects them.
Review at the end of the quarter
Look honestly at what was finished, what was not and why. Carry forward only what still matters. Then set the next quarter's commitments with what you learned.
Keep it visible
Put the commitments on one page or one board everyone can see. The rhythm only works if people can see progress, including their own.