2002 Honda Accord Please advise

Hi,

I saw this somewhere and had saved it from before:

Downshift when you need to. Some people spend their whole driving lives without ever using their lower driving gear. If your car seems to be struggling to go up a hill, help it along by downshifting. It doesn't take any time or effort and it really helps reduce the load on your engine. Accelerating when the car is hesitating puts a great deal of stress on the motor, It causes rapid wear and it also reduces the flow of oil, which makes your car work a whole lot harder than it needs to. Overburdening the engine will wear your car out faster than you realize. If you drive on very hilly or mountainous roads, downshift before the car starts to strain and you may add years to the life of your engine.

So, do you recommend shifting into 2 (I have 3 gears) when I go uphill and downhill? Would this be safe? Also, would I use more gas if I do? If so, would it be minimal or would it really guzzle gas?

Thanks.
A. Samuel