Disclaimer:
I'd like to apologize first for any and all of the probable grammar and syntactic mistakes, I know that this is the worst excuse but english is not my first language so I'm prone to get confused every now and then.
...him being who had to create, because... He had to.
Willie Trombone, son of Ottoborg
-The Neverhood
There comes a time in every roleplayer's life in which strange and new feelings begin to sprout deep within himself, an urge to create never felt before that cannot be quenched by just rolling a new character or weaving a new story, no, it seems like the only way to overcome these strange new needs is to come up with a whole new world. But a few villages, towns, castles and caves wont do, it must be unique, not something that can be easily attached to a previously created setting.
There's a myriad ways to achieve this, but to make things easier let's just say that there are only two possible paths. To build a setting for a game you know, or to build a setting and then look for the best system to play it.
More often than not, I walk the second path, I come up with a world without knowing for which game, so when I try to adapt my ideas to an already established system I usually grow dissatisfied with the results.
I'm mostly used to the d20 system, which I really like, for DnD and other WotC products. Most of my projects are stuffed in the magical freezer in the back of my head, waiting the moment I either find the system I'm looking for, modify an existing one or come up with a new one just for this world, all because I generally don't like levels and classes and the fact that every time you improve at something you also get more hit points. I am, however, using d20 for my homebrewed settings because, as I said before, it's the system both my players and myself are more familiar with.
So, looking forward to learn from the experience of other homebrewers I come here to ask you, how do you do it? Do you master a multitude of systems in order to always know which one you'll use? You resign yourself to homebrew to that one system you know well? You tweak a lot? You make your own rules?
Thanks in advance.