A special squarish age

[Chuck Chan created this little puzzle. Greg Nelson suggested introducing the name "squarish" in order to simplify the problem statement.]

Let’s say that a number is squarish if it is the product of two consecutive numbers. For example, 6 is squarish, because it is 2*3.

A friend of mine at Microsoft recently had a birthday. He said his age is now squarish. Moreover, since the previous time his age was a squarish number, a squarish number of years has passed. How many years would he have to wait until his age would have this property again?