Energy prices - we switched my father's provider to EDF last year and he now pays almost half of what NPower were charging!
The reason seems to be the two tier charges used by NPower, ie the first step (can't remember exactly how many units, sorry) were charged at a higher rate and the second step at a lower rate.
He lives alone and never actually reached that second step so always paid the high rate. EDF have the same rate for all their units so this is much better for him.
He doesn't have a computer so he used a comparison phone line that he found in the "Yours" magazine to discover this and (even though he doesn't like change) is very pleased he did it.
What gives you a warm feeling? 🥰