“Exposing to the right” is a well-known rule of thumb for maximizing image quality by pushing exposure to avoid noise, but the equation is changing as the quality of image sensors continues to improve. Ctein over at The Online Photographer writes,
In theory, you can still use the dubious right-hand rule. Just be careful to never blow out any pixels.
[...] Unless you’re sure you’re dealing with a low contrast subject, pushing your exposure to the high side makes it likely you’ll blow highlights. If you’re trying to improve your odds of getting a good exposure, pulling away from the right is a much smarter thing to do. If you know your subject is really high in contrast, pull far, far away from the right. Keep those highlights under control and let the shadows go where they may.
[...] Just, whatever you do, don’t expose to the right unless you’re absolutely positive there are no highlights to get blown. It was a questionable rule to begin with; these days I call it downright dangerous.
‘Expose to the Right’ is a Bunch of Bull [The Online Photographer]