There are several reasons why Tom is becoming what the government calls a "reemployed annuitant." Some will benefit his agency and others will make our life a little easier. But what it ultimately means is that he will tiptoe into retirement, will wade into it gradually rather than diving into the deep end.
Which is not to say he couldn't handle an immediate plunge into a life without his three-hour roundtrip commutes. He could, and in fact he will, since his new gig will be mostly telecommuting.
I'm the one who likes the gradual approach. I liken it to what the racehorse world calls "walking hots" — making sure thoroughbreds don't suddenly lurch from 60 to 0 and sicken themselves in the process. (This is something you learn when you grow up in Kentucky.)
Retirement is a word I never used to think about but has now come out of the closet. I'm not ready to contemplate it for myself (do writers ever really retire?), but when I do, the gradual approach that Tom is about to experience looks pretty good to me.