As often as I search for information on a completely new topic, that's as often as I find I have to go back and find information I have had to find before. For example, next year's schedule of trade shows and presentations in my field, or a list of State Fairs for my vacation. Or, somebody two desks down is asking me, for the fourth month in a row, to please get them the Consumer Price Index from the Bureau of Labor Statistics. This is where a library of key sites is so handy.
I have a section of Bookmarks in my Web browser, and a couple of backup copies as well, of sites I rely on regularly, like a site that lists holidays in countries around the world, and one that links to online newspaper and magazine editions.
Remember, whatever technique puts information you need on your screen the fastest means you spend less time looking for it and more time using it. Whatever your professional field, whatever your personal interests, key sites are a valuable part of your search strategy.