USA Today: There’s longevity. There’s stamina. And then, there’s David Letterman, who, after he retires Wednesday, will have hosted 6,028 late-night talk-show broadcasts over 33 years. Letterman, 68, was master of the acerbic interview: Probing entertainers and politicians alike, he was neither sycophantic, predictable nor encumbered by the late-night tradition of softball questions. Which is why, says frequent guest Olivia Wilde, “He doesn’t seem to be working for a network.”