A first aid at work certificate lasts for three years. This means that the person can fulfil the role of a workplace first aider for those three years. If your certificate expires you cannot fulfil the role of a workplace first aider and an employer may not be providing the necessary first aid provision that their risk assessment identifies.
A regulated qualification is valid for three years, and studies have shown that the quality of first aid skills can deteriorate after 6 months. Known as skill fade. The HSE strongly recommends that first aiders complete an annual refresher of their first aid skills.