I wouldn't be too worried about carrying parts for the carrier itself, if in the rare instance you do have a failure, your going to need to pull the axle apart, access damage and order the needed parts. ARB USA has a good parts supply. I may consider carrying a set of o-rings for the seal housing and a bulkhead fitting kit. Beyond that, I would carry spare blue line and a splice kit, ARB offers a really nice packaged kit that comes with line, a double ended push-lock splice and some bulkhead fitting parts, part# ASK001.