Investing is one of those things that can be as complicated as you want it to be. For hobbyists and professionals, there are endless books to read and ideas to ponder. For the ordinary person, who just wants peace of mind, there are only a few bedrock ideas.  The bedrock ideas are the obvious place to start. Over time we can broaden out into fancier, more esoteric stuff. But we’ll keep one hand at all times on the basics, since they’re what actually make a difference to most people’s investing returns. Today I want to expand a bit on the idea…