A guide to determining whether older and existing PowerBook designs will remain viable in the future is presented. Apple is preparing to ship PowerPC-based PowerBooks that will offer built-in PCMCIA support, an infrared interface and state-of-the-art battery technology, but these are incremental improvements. As new hardware, the next-generation PowerBooks will command premium prices. An alternative for PowerBook 500-series and Duo owners is a processor upgrade, although it is less compelling if the PowerBook is not the user's primary Mac. The 500 series has more hardware features than any PowerBook before or since, with built-in Ethernet, an internal modem and two batteries, but they are heavy and bulky. The Duos remain good subnotebook machines. Older PowerBooks, including the 140 to 180, are showing their age and have relatively weak nickel-cadmium batteries. The PowerBook 100 is in some ways the best PowerBook ever made, but software and batteries for it are difficult to get. Owners of the PB100 and the Mac Portable remain loyal to their machines, and upgrades will be available.