As part of our work on International Roaming, we see today's advanced, "quad-band" cellular phone as tomorrow's old school technology. Some of today's networks require a "tri-band" phone just for "normal" US coverage. Cricket uses the third band for additional markets, T-Mobile uses it for much of their 3G coverage. And there's more coming. There are 5 such wireless "bands" on the air today.
Verizon, and others, are working on 700 MHz services, and the FCC is looking for a few more slices of spectrum pie to feed our insatiable need for bandwidth. Fortunately, the manufacturers are keeping up with the RF requirements, but we see clouds on the horizon. Much like the brick wall that prevents the cross-use of GSM and CDMA networks, the need for so many new frequency bands, and phones that serve them, may provide a similar stumbling block.
Sure, technology should be able to come to the rescue, but are we ready to face the need for new equipment every few years? Some Americans replace their phones almost that often, but to be required to do so may reach a resistance level. And we haven't put much thought as to what is happening overseas. India is having a spectrum auction right now that will add to the bowl of band soup.
Besides, a "sex-band" phone (sex = 6) does have a certain ring to it.