It depends. If you're extremely lucky and/or careful, you shouldn't need one. Otherwise, go for it. I had my my 3670 replaced several times on a CarePaq: digitizer developed dead zones twice, rom toasted once (my fault), sync connector quit functioning completely and a cracked LCD. Read the TOS though; cracked LCDs aren't covered by the standard Care Pack although there was nothing in my documentation stating otherwise.
Btw, they're now referred to as Care Packs.
