WASHINGTON — It used to be that a letter sent was a letter delivered.
Not so much anymore. Even before the Postal Service begins closing hundreds of processing centers to cut costs, several businesses say they are already beginning to see a decline in service.
Dozens of local newspapers say papers are being delivered late or not at all, causing them to lose advertisers and subscribers.
‘‘The problems only seem to be getting worse,’’ said Max Heath, a consultant for Publishing Group of America, which publishes magazines distributed through small newspapers.
A decline in mail volume, particularly first-class mail, which accounts for the bulk of revenue, has produced steady losses for the Postal Service — an average of $1 billion a month in the first half of the fiscal year — and forced it to propose closing about half its processing centers and cutting hundreds of thousands of jobs.