While I may not stay quite THIS conservative, I like to brew a tried and true recipe from an experienced brewer who has provided brewing and tasting notes to see how well I like it and how close I get to the original. From there I will tweak it based on my personal tastes and what I have on hand.
I truly feel that great brewing is like great art...you have to know the rules and how to follow them in order to know how to break them right
Anyone can throw a bunch of crap in a kettle and call it beer. A brewer crafts his recipes, walking the line between style, personal preference, and experimentation.