Each year, towards the the end of the fiscal year (around September), military commands around the world scrammble to spend the remaining money in their budget for fear that their funding for the next fiscal year will be cut (take a mark).
Rather than penalizing commands for not spending their money, they should be rewarded for their savings. A small portion of the money they turn back should be given back to the command to use for a bonus or morale boosting event.
Additionally, they should not fear taking a hit on the next year's budget, but rather be given an incentive to reduce spending again, this time by an even larger percentage.
This alone would save billions of dollars while improving morale of workers.