Several signs indicate that your fire extinguisher may need to be replaced. First, if you notice physical damage or corrosion on the exterior of the extinguisher, that can be a sign that it is ready to be replaced.   Furthermore, if the pressure gauge on the extinguisher indicates low-pressure levels or if it appears sluggish when pressing the release lever, these may also indicate a need for replacement.   Finally, if you have not used your fire extinguisher in several years and can no longer find any evidence of an inspection date printed on its sides, this could also mean that it needs to be replaced.