Normally that's a good thing. Consumers keep buying while workplaces cut back on IT spending. But Moskowitz believes the current economic slump is different:

"In prior recessions, the consumer had been fairly resilient, but mounting job losses, shrinking home values, and tight credit stand to make the current recession quite more challenging. We believe that the next few quarters stand to get bumpy."

Moskowitz cut his Mac shipment estimate to 2.19 million from 2.39 million. He also lowered iPhone shipment targets to 3.4 million from 3.8 million.

TheStreet.com reporter Scott Moritz that Apple's loyal consumers aren't likely to upgrade to the company's latest models.

"With U.S. unemployment now at 8.1%, it's hard to imagine consumers rushing out to buy new computers. And increasingly, when they do, they are opting for [US]$300 stripped-down models called netbooks from Asian manufacturers like Asus and Acer."