Achieving Celtics Immortality: Will No. 5 Hang From The Rafters?

A close friend and I were joking the other day that the Celtics cannot afford to retire too many more jersey numbers without creating the need to start using three digit numbers. 

Paul Pierce's No. 34 was our consensus choice for the next number to hang from the rafters in the Garden, but we debated about whose might follow. 

I suggested that Kevin Garnett's No. 5 was a possibility if he can somehow bring two more championship banners to Boston over the next three years. 

My friend rightfully pointed out that this was highly unlikely, but it raised an interesting question of whether or not KG would deserve the honor if he somehow managed to secure banners 18 and 19.

I argued that KG would be a lock for having his number retired in such circumstances, but my friend insisted that he would need to play more than four years as a Celtic to warrant the honor.

Are four years too few?

The Celtics have retired the numbers of two players— Ed Macauley (No. 22) and Reggie Lewis (No. 35)— who each played for just six seasons.

Interestingly, neither of them played on a championship team.

If KG plays just four seasons in green but brings home the bacon three times during that span, shouldn't he have his No. 5 retired?

If so, then what about Ray Allen's No. 20 if he also plays on those hypothetical championship teams?

What do you think?

What criteria should the Celtics or any other NBA team use as the basis for retiring a number?

Who will follow Pierce for the Celtics?

Does KG have a chance?