I think most people would feel comfortable doing it themselves once they've seen it done one time. It's not hard to do and as long as you are careful the process is very straight forward. Anyone who has ever worked around acids before should have no problem. If the whole acid thing scares you then there is always the 6 pack for service offer as long as you help me drink em.
You can also pick up a couple of extra cartridges and the resin in bulk. So you can use a few of them up before getting them recharged. I do this myself. Use them, then bulk recharge them all at the same time.
Carlo