When slowing down, what is a good practice?

When slowing down, checking behind you is vital for safe driving. It allows you to be aware of the traffic situation behind your vehicle. This is especially important because when you reduce your speed, vehicles that are following you may not expect you to do so, and they may not be able to stop in time if they are too close. By checking your mirrors, you can assess whether there are vehicles approaching quickly or if there is enough distance between you and the cars behind you, helping you to make safer decisions.

While checking your speedometer can help ensure you're within the legal speed limit, it doesn't provide information about the surrounding traffic conditions or the potential actions of drivers behind you. Accelerating slightly contrary to the objective of slowing down, and turning on hazard lights may not be necessary or appropriate in most situations when simply reducing speed.