After years of looking at your same old logo I'm sure the questions arises: Is it time for a new logo? Obviously the brand you put forth has a large bearing in regards to customer attraction but designing a new logo can be risky. You need to ask yourself the following questions:

Is it worth the time/money?
Well that depends. How long have you had your current logo? Has the initial investment paid for itself? Do I want to risk looking unprofessional by either keeping an out-dated logo or trying to update it myself?

Is your logo "out of style"?
Although an established brand is an important thing, an old/out of date logo can send out the wrong signal. Fonts and typefaces do go out of style and certain icons or illustrations can look dated over time. Although it is impossible to come up with something that would be considered 100% timeless, it is important to avoid being trendy when it comes to logos/brands.

Is it worth the risk?
Again that depends on your answers to the questions above. Most of the largest, most recognizable companies update their logo every 5 years or so. They can still maintain their brand via subtle clues and connections with their older logo styles, but a simple font or layout change can do wonders and really says a lot about the dynamic nature and willingness to progress for a company. Nike will always keep their "swoosh" symbol but they change their corporate font and the branding around the logo continually.

Has your business grown or changed direction?
Maybe when you started your business you had a limited (or non-existent) budget and you hired your nephew to create something in CorelDraw for you. Maybe the scope or direction of your business has changed and the icon or font you use is no longer relevant. These are all things to consider.

To recap, regardless of which direction you go there is risk. You need to figure out which risk is worth taking.