Bi-yearly visits are best . . .
I've always enjoyed the Sawdust Festival, however, attending it every other year -- or every two years -- increases the enjoyment much more. The same vendors tend to show every year, and it's boring to already know in advance the art I'll see. But if I break up the years that I attend, I find I enjoy my time there immensely.
Parking in any California beach city is a hassle, so knowing that in advance I just pay the closest parking lot price and forget about it . . . I've paid more for a pizza and enjoyed it less. If possible, go during the week days, especially when the show first opens. But if you don't mind lots of people, the weekend is equally enjoyable.
I also hit the other two art shows while I'm there, and enjoy them, too. If you like art, you'll enjoy this two month showing by local artists. Wear comfortable shoes!! :)