Do I need an electrician to replace a light fitting?

The distinction that matters is not how simple the job looks. It is whether the fitting connects to the mains by a plug or by fixed wiring. A lamp you plug into a socket is yours to do whatever you like with. A fitting wired into the ceiling is part of the building's fixed wiring, and disconnecting and reconnecting it is electrical work under every state and territory's licensing regime.123

Australia is unusual here. Some countries allow limited householder electrical work under a permit or inspection scheme; Australia does not. There is no equivalent of a homeowner permit for fixed wiring in any jurisdiction.

What it means in practice

• Doing the work yourself is an offence under state electrical safety law, separate from any consequence if something goes wrong.
• Home and contents insurers commonly decline claims arising from unlicensed electrical work. That exposure long outlives the job.
• Work done by a licensed electrician comes with a certificate of electrical safety or the equivalent in your state. Keep it. It is the document that proves the work was compliant when you sell.123

What you can do yourself

• Anything that connects by a plug and socket, including plug-in lamps and extension leads.
• Replacing a globe in an existing fitting.
• Resetting a tripped circuit breaker or safety switch at the switchboard, though a breaker that trips repeatedly is telling you something and needs looking at.