Driving in NEUTRAL down a hill instead of in Gear in a Manual car.?

Good:

1) Slightly less wear on your valves and engine block, because the engine is moving slower.

Bad

1) You are using more fuel in neutral rolling down the hill because the engine is idleing. If it were in gear and you are not applying any throttle, It will not use any fuel (at least if the car is built recently and has a computer engine management), and therefore get infinitely many mpgs :D

2) You will wear your breaks, because you are more likely to keep the speed under control with the break, instead of having the engine slow the car down.

3) You have less control over the car. If you needed to accelerate to get out of a dangerous situation, you would first have to put the car in gear, as opposed to just having to open the throttle.

Neutral Gear

It's definitely not for everyone. If you can't throw it in the correct gear for the speed/rpms, rev-match and engage in under a second, you're just not a 'good enough' manual-transmission driver to attempt this.

Like they say, a little knowledge is a dangerous thing.

The one good point that I can think of, is when something feels 'wrong'about the car, and you want to trouble shoot, rolling down a hill in neutral will help you determine a few things like a seized brake caliper, or bad alignment, etc.

Bad practise. You would fail driving test in UK. You have much less control, as if you need to accelerate there will be delay. Also it can put more load on the brakes than necessary which can lead to brake fade when you don't want it! Brake wear will increase too.

There are no good points. Bad points are that you have far less control, you may not get back into gear at the point you want to, it used more fuel on a modern car.

Inviting trouble. You can not control the vehicle as 'G" force will be greater. Gears act as a brake when driving down the gradient.

Don't do it, I thought same thing. save on breaks.

It slipped into reverse! You need to be in control of your car at all times when driving, and if your moving in neutral. your coasting, your not in control.

It is illegal to coast a vehicle for any reason and downhill is recklessly dangerous!