Registration helps deter potential infringers. It assists you in avoiding infringing other peoples' rights as the process of registration includes a check for similar trademarks. Once you are registered, if anyone challenges your right to the trademark, the onus will be on the challenger to prove infringement, which enables you to more easily protect your trademark against someone claiming infringement. By registering in Canada, you obtain protection in Canada for a renewable 15-year period. By registering in the US you obtain protection in the US for a renewable 10-year period.
Average time is twelve months.
A trademark agent is not required. A new twist with the internet is that you are potentially offering your goods or services to the world at large but will be protected only in the countries in which you register. Unless you search every business name and trademark database world-wide, you can not be assured that your domain name is not the same or similar to a business name or trademark in a different jurisdiction. Where two parties each have a legitimate claim to the same or a similar name, it is currently unclear how a court would decide the issue.