I always stress consistency in radio programming. Quick unexpected changes will lose audiences. I once worked for a popular standards radio station in north Jersey. It always had marketing problems along with signal problems but it did have a core audience who loved hearing Ella Fitzgerald, Frank Sinatra, Tony Bennett and the like.
The owners could never keep a sales staff for one reason or the other. Sometimes "mom and pop" companies are good but their micro - management could destroy a station! This station began adding infomercials interrupting the music programming throughout the day. The audience left in droves! The dedicated audience that the station once had was now gone!
It's great to make subtle changes to programming like adding new jingles or imaging. Creating exciting promotions is also another way to keep things fresh. Edgewater Gold Radio consistently plays oldies from the 50s through the 80's. I will always search for additional songs to add to the library. I also add different types of shows like our 60s and 70s weekends and Nightmemories in which we play softer oldies and mix them with standards every weekday evening. I'm not straying from my oldies format, just mixing it up a bit.
I'm currently going to make a change to our weekend programming by adding a new show. I will not lay out the details until I iron some things out. Look for the debut of this new show in the next few weeks.
Keep it consistent, fresh and keep your audience tuned in!