Many people have asked about how long a certain certification lasts for. The two main providers, the Red Cross and the Lifesaving Society, have some different courses with different certificates. Standard First Aid and Emergency First Aid are valid for two years under the Lifesaving Society and three years under the Red Cross. CPR courses are valid for three years by the Red Cross and two years by the Lifesaving Society. However, annual recertification is recommended by both providers. The Lifesaving Society offers two AED courses, AED responder and AED provider, both of which are valid for two years.
Keep in mind that your workplace can set a standard for how long your certifications are current for. City of Vancouver lifeguards are required to re-certify their Standard First Aid (http://vancouverfirstaid.ca/recertification-courses/first-aid-recertifications/standard-first-aid-recertifications/) every two years, regardless of what it says on the card. Check with your employer to see if they have set a recertification standard for you to follow.
Hope this helps.