It all counts for twenty.

In this post, I mentioned the phrase "it all counts on twenty."  I got curious about the phrase and googled it.  I only found a couple of references

, neither of which had a definition, although both of them made it clear that it was Navy slang.

So I took the question to the Straight Dope Message Board. Apparently, the actual phrase is either "it all counts for twenty (or thirty)" or "it all counts against twenty." The twenty in question is the number of years that had to be served before retirement. If you're stuck with a particularly boring or nasty job, you shrug it off with "it all counts for twenty," or it may be a nasty job, but it's getting me that much closer to retiring.

Letters from dead people can be educational.