Fire extinguishers should be visually inspected at least once per month to check for physical damage, pressure gauge status, accessibility, and safety seals. They also require a professional maintenance inspection once per year to ensure full functionality and compliance with standards. Additionally, internal maintenance inspections and hydrostatic testing are needed every 5 to 12 years depending on the type of extinguisher. This schedule ensures fire extinguishers remain reliable and effective in case of an emergency.