New to central heat and air so getting up to speed; i.e. in time will have many questions

In meantime, while visiting sister couple of years ago I assisted her husband [ok, held flashlight, but hey, I held it very steady and in right direction] while he took out flame rod?/sensor? and sanded it. Furnace had stopped working and once he sanded flame rod?/sensor? the furnace worked and has been working since then.

From reading several pages in this thread the sanding is not regular mtce item and questionable as well.

My question is if a new flame rod?/sensor? would be more appropriate as it would result in better running/efficient furnace or it would not make a difference?

Thanks.