A great logo should last at least 10 years as is, a lot more if you allow for minor modifications along the way. Take the example of Coca-Cola and Pepsi
If you look at Coca-Cola’s logo in 1900 you can still identify it very clearly. In fact, modifications since the red colour was introduced have been very minor. In contrast, Pepsi has changed pretty radically. In your opinion, which is the most universally recognized logo?
In order for your logo to be timeless, try not to be seduced by flashy trends. Once again, keep it simple and in line with your brand message and you shouldn’t have any bad surprises.
However, if you are feeling that your logo needs to be freshened up a bit, don’t hesitate to check our post "Do I need to redesign my logo?" for tips.