When I first started collecting coins- I stashed some centennial change once the coins started dwindling from circulation. I then started note collecting later, in the mid 1970's once I noticed the 1954 notes being replaced by the multicoloured series. I really enjoyed collecting in those days - just for the joy of trying to get each denomination or a signature series acquired.
Going to universities, and jobless for some time, it was a while before I could get into note collecting in any serious way again. I had a few spells of employment where I could buy the odd Devil's Face at those dealer stands set up at our local mall.
When I finally resumed collecting (around 2002), the Journeys were emerging to replace the Bird series. At this time, I was learning about the FEE changeover, FDY and other prefixes I could pull out of circulation. It was an exciting time to collect because there were relatively rare notes out there to just pluck from circulation, or large bank withdrawals. The last thing on my mind (even then) was grading a note.
Okay- so it took me a while to get with the grading program, and eventually I learned (sure it was the hard way-- but I learned). What made the hobby more interesting was the info I could get here (on line) or through the Charlton book.
Now is also an exciting time to collect with the new Governor, signature and prefix changeovers, etc.
If I were a "newbie" entering this hobby-- I would attend the local shows & learn to grade while collecting the stuff that's out there. I would also seek the advice of the veteran seasoned collectors (but be judicious in what you follow), while trying to focus on collecting a particular series, replacements, radars, or the like. I think having a clear direction in this hobby helps keep one focused. It also allows you to sell (or trade) notes that can be used for more desirable acquisitions.
Hope this helps.
W_T_T_W