I would honestly say expert. why? because of the years I spent working at the LFS, looking after so many different species, saltwater, reefs, 6 foot nurse shark etc etc.
I learned more in 1 year there than many years on my own. after all, they had 180 tanks, a 1500g shark tank etc. I have two tanks at home LOL
also, you learn so much in talking to customers there, there isn't much I haven't seen at one time or another.
that being said, you can't know everything. this hobby is a constant source of learning.
so just because you might consider yourself an expert, you still learn new things all the time. thats just the nature of the hobby.