Injector question

Hi. I have some problems with my injectors being worn. I have had one injector refurbed as it was missing on that cylinder and smoking badly, now the engine runs better but there is still smoke but less of it. So now my attention turns to the other three..and I'm keen to avoid the expense of a diesel shop refurb.

My question is this, when the diesel shop refurbed my injector they got a nozzle repair kit which also seems to include the offset bushing, as he gave my old one back. I intend to buy new nozzles for the other three and swap them myself but I notice the nozzles do not come with the offset bushing. Does the offset bushing wear out? I'm worried I'll swap to new nozzles and then find I have another worn offset bushing, but won't be able to buy the offset bushing with out having to buy a full nozzle repair kit!!

I would buy a full nozzle repair kit in the first place but the only one I can find on the web is the same price as getting it refurbed at the shop.