Some companies seem to belong to the logo-of-the-month club and feel the need to change their visual identity with amazing frequency. Then there is the odd company that keeps hanging on to a clearly outdated logo that should have been gone years ago.
Many companies are somewhere inbetween. Take a look at this graphic that makes a visual comparison of the Pepsi® and Coca-Cola® logos over the years (from the designnotes.info blog):
Looking at them side by side, it is interesting to see how the logos have evolved over the years. I leave it to you to draw conclusions about the wisdom of the Coca-Cola folks in keeping their logo very consistent over the years, versus Pepsi’s total makeovers along the way.
Notice though how Coca-Cola introduced a completely new logo in 1985, along with the new coke. And in a short period of time, both were gone. When the new formula fizzled, the best way to reassure customers that Coca-Cola had returned to the original formula was to return to the old logo (note how in 1987, the new Coke logo was still tucked in under the main logo, to help in the transition).
If your company has a logo that works, then don’t look to change, just because you can. There should be good reasons, and anytime you do change logos, consider not only the cost of the process (design, replacing materials and signs that have the old logo, and customer confusion), but also very carefully consider what the new logo does better than the old logo. And don’t trade something dated for something that is hip today and will look so dated just a year or two from now.
After all, your logo is a key part to your branding. It should be handled with care.