Depends - using support/resistance definitely works.
As far as the old (many decades old - before easy access to computers) pivot point formulas you now find in books or referenced on websites, they've been routinely replaced by more and more sophisticated computerized methods by many of the technical trading firms.
Also, trading support/resistance isn't as simple as automatically selling resistance and buying support. You've got to take some specific and macro factors into consideration too.
But knowing where the S/R areas are gives you the ability to focus. You can then look for signs of fading momentum or increased selling near resistance (or accelerated buying in the case of a breakout through resistance).