A different way to collect a series
I have always enjoyed collecting a series rather than a type set. I have found that I like the challenge of finding that date I need. Also, when you collect a series you really do become an expert and often you know more than 90% of the dealers because you have immersed yourself.
The biggest drawback I hear from collectors is they dont like having to buy common uninteresting coins to complete their set. I emphasize with that sentiment. For instance when I collected lib quarter eagles I had no desire to spend money on the 1900-1907 dates. I knew they were always available and I rather use my money on a dahlonega coin or a rare philly date.
My new philosophy collecting a series is simply to ignore the most common dates. No one can tell me that if I have 3/4 of all dates in the lib quarter eagle series and am missing the most common dates that my set is any less desirable (ie I doubt you will hear "I love your 1845-O, 1850-D , etc but where are the 1900 -1907 qes). One could pick any series and eliminate 10% or 20% or even 50% of the most common dates and complete the rest. This is not a box of 20 philosophy---it is collecting a series but not wasting your money on the easiest coins to find. And at the end if you want to "complete" your set then the easiest dates by definition will always be available.
I'm not suggesting this is the "right" way but it is an option for a collector who wants to collect a series but not be burdened by coins he doesnt really want. Completing almost any series without 20% (or any other number) of the easiest dates will be challenging, educational and leave you with a very desirable set.