There are a lot of reasons why you should have a jingle.  Here are just a few of them:

• Jingles save you money.  While your advertising jingle is being aired, the tune gets stuck in the listener’s brain.  That way you can air it less frequently to achieve the same awareness.
• Major companies ALWAYS use jingles.  The most successful business advertising campaigns in history were always accompanied by a memorable jingle. 
• Radio stations will feature your jingle in their spot rotations.  When radio stations like a particular jingle, they usually feature that spot at the very beginning of their commercials. 
• Jingles build a favorable attitude towards you from the radio stations.  Radio stations love jingles because more people tune in to music than spoken advertising. 
• Canned music is non-exclusive.  Having the same music as another company, or worse, your competitor, totally negates having advertising. Custom music benefits any spot.
• Radio jingles build greater campaigns.  People change stations when they hear talking over the radio.  When they hear music, it grabs their attention and stops them from changing the station.
• Research shows that jingles are ten times more memorable than a talkie.  Radio and tv jingles become as identifiable as your logo – the very first step in becoming a household name.
• If you have a commercial jingle and your competitor doesn’t: you are going to win the race