For instance, if I know it's going to be expensive when I'd be cooking tomorrow's evening meal, then I won't make something that would need a long time in the oven. And if it's going to be particularly cheap around lunchtime, then I'll plan to do a big load of laundry then.
I have electric heating, which I thought might be a cause of anxiety but it's not really worked out that way. The temperature in my flat won't go down by more than a degree or two with the heating off over the course of the sort of 4 hour price spikes you tend to see in mid-January. If it looks like it's going to be unusually bad, I could always raise the temp by half a degree beforehand, but in reality I've only bothered to do that maybe three times in the past couple of years.
Basically, it's just another thing to factor in when planning my day. No more of a hassle than checking the weather forecast or glancing at my calendar.