Brake light replacement?

When you change the tail lights, do you have to replace the entire board on a 2002 Envoy? I wouldn't have thought so, but a local parts store showed me that simply replacing the light will cause it to blow. I am not very automotive-minded, but that just doesn't make sense. Please help?

I just replaced a turn signal - no problems

you do not have to replace the entire board but if you have a problem that the same bulb keeps going out you have to replace the board if you are under the 3/36 warranty the dealer should replace both due to a bulletin that states to do so.

Bullutin 04017...........now 6/116,000kms
Gm should change the tail lamp board.