Couldn't agree more, although if you're anything like me, you learn as you go along. As I started collecting, I also started to buy books and learn.
One thing of considerable note IMO - that once you are deep into collecting your chosen speciality, the increasig breadth of technical and other knowledge you hold about that speciality, will stand you in very good stead both for avoiding being ripped off, and possibly even more importantly, recognising a bargain and/or a prized acquisition.
Keep at it Jamie and good luck