The most common mistake first time DIYers make wiring a light switch

[GlobalBob37]

The single biggest mistake is not actually turning off power at the breaker before starting, relying instead on the wall switch itself being off, which does not guarantee the wire is safely dead depending on how the circuit is actually wired. This is genuinely the single most dangerous mistake on this entire list and the one most likely to cause real serious harm.

A closely related mistake is not testing the wire with an actual voltage tester after flipping the breaker. Assuming the breaker is correctly labeled when household breaker panels are notoriously often mislabeled or only partially accurate, meaning a wire someone assumes is dead may genuinely still be live.

People also frequently mix up the hot and neutral wires or fail to properly identify which wire does what in a genuinely more complex three way switch setup. Leading to a switch that technically works but is wired in a way that creates a real ongoing fire risk over time.

Another common trap is using wire nuts or connections that are too loose. Either from inexperience or from rushing the job, which can create resistance at the connection point that genuinely generates real heat over time, a slow developing hazard that isn't obvious immediately after finishing the job.

The honest summary is that most of what goes wrong here comes from skipping genuine safety verification steps. Breaker off, voltage tested, connections properly secured, rather than actual mechanical wiring skill, and none of this should be attempted without being fully confident about each specific safety step along the way

[Aaron]

Nice breakdown! The safety verification over mechanical skill framing applies to basically all electrical work, not just this one specific task