I remembered a time when my space marines collection consists of 10 humble AOTBR marines and 5 terminators, together with their captain and dreadnought they were the only member of my chapter. Searching for their identity and place in the 40k universe they quickly settled under the banner of Purgation Lords and the chapter grew... second squad tactical marines, first rhino, second rhino, third tactical squad, third rhino. Then landraider, which became landraiders, land speeder, land speeder squadron then land speeder squadrons.
In time my chapter grew and grew as of now I have one third of the first company on stand by with their multiple landraiders. Three full squads of tactical marines ( which hardly see any action these days, but that is another story...) with their rides, full spectrum devastators, land speeder squadrons and a school of dreadnoughts with all known useful configurations, and last but not least a dozen of raw recruits.
Then heroes emerges from my chapter to lead them, first a captain, then a librarian, a chaplain, then more captains...it got until then point I almost have a Doppelgänger for every named character in Codex: SM, Sgt Chronos being one of exception not cloned into my chapter, yet.
Having such a huge arsenal of war machines, a hall full of heroes and gangs of battle brothers at your disposal is certainly fun to begin with, but then eventually I noticed another way of collecting army which might be more interesting and the apparent pros and cons of 2 main method of army collection.
-end of part 1