First off, video doesn't have to be expensive--nor does it have to be a clip of live action. Repurposing 30-second spots is great if a company already has them, but creating high quality how-to videos, interviews and even photo slideshows set to music can be just as effective.
But video--just like all searchable content--must be fresh and updated. "Now, the timeframe of what is 'fresh' depends on the business and web site traffic composition," Pingul says. "But the meta point is keep it fresh!"