Irving Schlaifer's 1981 Checker cab has gone 84,000 miles, and he's finding it harder and costlier to keep it repaired. Downtown development is the chief culprit. But, on the other hand, the scrupulously maintained vehicle had a day in the sun this year when it was rented for an appearance in a movie.

Irv, an absolutely devoted taxicab driver and knowledgeable tour guide, has been an inside gadfly in Washington's cab industry at least since the picture at the right accompanied an interview in The Washington Post in 1952.

Having known him since about 1957, I was a bit concerned when Irv's annual holiday letter didn't show up in the mail.

Instead, it was hand-delivered at our front desk, all five tightly spaced legal pages of it.

What's new with Irv and wife Emma?

Well, lots of relatives trooped through town, including Irv's sister-in-law Lois Schlaifer from California, who was taken to see Arlington Hall, where she had been stationed as a female soldier during World War II.

News about the cab took a major chunk of Irv's letter. Nick, his repairman, lost the location of his former four-stall repair garage near the Convention Center, blaming development pressures. Nick says he cannot afford "the outrageous rents" demanded by other landlords, so has left the trade for now.

Meantime, Irv is paying a Chevrolet dealership $38 an hour for repair work. A South Carolina mechanic recently took a tour with Irv and said that the comparable price down home is $20.

Irv's Checker was rented for one day, last March 15, "to be used in a TV movie starring Robert Wagner . . . [who] played the part of an insurance company investigator." The cab, Irv said, "was very well paid" but, alas, Irv didn't get to drive.

Two other items. Foxey, the Schlaifers' longhaired orange cat -- pictured on a card two years ago lying belly-up in a bathroom wash basin -- died of feline leukemia, and has been replaced by two sisters, Twiggy and Leafy.

And Irv himself underwent in May "the same kind of colon [cancer] operation that President Ronald Reagan had." Prognosis, like the president's: excellent.