US Postal Service

Currently, mail is delivered to residences 6 days each week across the country.

Almost no mail delivery is time-sensitive anymore. It is either advertisements, magazines, or bills. Together these add up to 3 or 4 pieces of mail per day, on average. 

Change mail delivery to three times per week. Either MWF or TThS. This would not harm citizens and would actually save them a little time. 

Primary benefit: The USPS could operate with half as many mail delivery personnel.

Recommendation: Implement with patience. No USPS employees need be laid off. Hold off hiring until attrition has brought the USPS to the needed level. The process might take ten years but it still means the USPS would be able to reduce its budget every one of those ten years.