A power surge is a brief, sudden increase in voltage that can damage sensitive electronics, and surge protection is designed to absorb or redirect that excess voltage before it reaches your appliances.
Lightning strikes are the most dramatic cause, but more common culprits are the grid switching load, or large appliances like air conditioners and pool pumps switching on and off within your own home.
Plug-in surge protectors (like a surge-protected power board) only protect what's plugged into them. A surge protection device fitted at the switchboard protects everything connected to your home's wiring at once.
If your home has expensive electronics, smart home systems, solar inverters, or you've experienced surge damage before, whole-home surge protection is a relatively small cost against the potential damage bill.
Switchboard-level surge protection is a straightforward addition for a licensed electrician to fit during a switchboard upgrade or as a standalone job.