Even if you have gone to the trouble of registering your trade-marks, there are many ways that you can lose them. Here are a few of them:

1. Allow related companies to use your trade-marks without having a written license agreement in place that meets the requirements of the Trade-Marks Act.
2. Do a corporate reorganization for tax purposes that changes the ownership of the trade-marks without formally transferring the trade-marks under the Trade-Marks Act or without changing the trade-mark notices on your products or marketing materials or taking other steps to make the public aware of the change.
3. Change your address or your lawyers and do not update the address for service with the Registrar of Trade-Marks so that you do not receive notice when your trade-mark has to be renewed after 15 years.
4. Make changes to the trade-mark, such as updating the logo, so you cannot prove use of the trade-mark as registered.
5. Allow third parties to use the same trade-mark for similar goods or services without challenging their right to do so.
6. If you receive a notice from the Registrar of Trade-Marks requiring you to prove that you are still using the trade-mark, do not immediately get professional help to respond.