Radio stations are unique in the fact they can change their identity overnight.

A format change may include new call letters to reflect the format, music, talk, etc.

In some cases, a change is made before a competitor does. What comes to mind is 105.9 FM. WBBM-AM added their news format to the FM frequency and uses WCFS-FM. What pushed them was the threat of news on the 101.1 frequency if my memory serves me well.

Which Chicago station has gone through the most format changes? The 94.7 FM frequency comes to mind. We do have 100.3 which is a master of format tweaks/adjustments.

Finally, how about Chicago stations who have remained true to their format? WXRT-FM 93.1 is one. WFMT-FM 98.7 is another.

Music is so splintered these days, it's hard to serve a particular audience. Can you imagine back in the day, a mainstream AOR station playing Chicago and Hall & Oates next to AC/DC and Led Zeppelin? How much heavy metal is too much? The same for softer rock such as the Eagles for example?

Are radio consultants effective or is it a waste of money?

Speaking of conflicting music, how is WCHI-FM 95.5 doing these days? Is anyone listening?