I have 50 years experience in collecting ASFE (A Stamp From Everywhere), so my recommendation, as I saw much discussion on lists.
The ASFE collector should use 2 lists. The objective and the subjective one.
The objective one (you can google it at ASFE Slovakia site as Updated List of 780 ASFE stamp issuing entities ) serves for comparison how ASFE collectors are advanced. Do not expect to collect it in one month, even one year or one decade. I have never heard of anybody to have completed it. The list is named 780, as it is number of entities in Stamp Atlas by Mr. Hlinka from 1971. And updated, as 1971 was rather long ago....
The subjective list is the one you adjust for your needs. I have added local stamps, telegraphic stamps, 21 thousand precancels and even some artistamps (Cinderellas) and revenues. And I have based on it my wantlist. You can see it on that site of ASFE Slovakia. The goal is to get offers.
I just finished my end of 2017 collection statistics and can share a couple of things which may be relevant to this thread. 1. Based in North America, my catalog budget goes to Scott - have 2012/2013 volumes - and my worldwide collection is now 21,772. 2. Also just finished compiling all the different entities in Scott - 690. 3. My collection has 373 different stamp collecting entities as per Scott, so 54% of the total. 4. This is based on a peanuts budget so I would say it is very possible to get close to a complete ASFE collection - say 90%, not withstanding that the first 50% of countries is much easier than second 50%.