In terms of water-based systems, which of the following is not typically inspected annually?

The correct choice is that fire extinguisher placements are typically not inspected annually in the same manner as the other options listed. Fire extinguishers require a different inspection protocol, often involving monthly visual inspections by a designated personnel, and more comprehensive servicing performed on an annual basis or as necessitated by specific regulations.

In contrast, sprinkler heads, standpipe systems, and dry pipe valves are essential components of fire protection systems that are subjected to annual inspections to ensure that they operate effectively and meet safety standards. Inspecting these systems regularly helps identify potential issues that could impede their function during a fire emergency, such as obstructions, corrosion, or leaks. Therefore, while fire extinguishers are critical for fire safety, their inspection and maintenance protocol differs from the routine inspections required for water-based suppression systems.