I heard that it is not a good idea to use the 2 and 1 manual gears a lot when driving cause it hurts the trans. Is this true?

as long as you dont stay in those gears while at high rpms. I sometimes will shift down to 2 or 1 if i know the car can handle it. If I am in 3 and need to downshift I will put it in 2 and hit the gas. Just watch your tac.

Also, you can downshift to 2 or 1 if you are on a slippery down-hill surface and dont want to slide due to using the brake. I have done that in the past.