If you have never switched, then you can save a couple of hundred quid a year. We tend to switch to the best fixed rate tariffs every couple of years. Think last time we saved another £40 switching from NPower to Ovo earlier in the year, but the more you switch the more you get into diminishing returns. Below a £2 a month saving, I wouldn’t bother.
Only time we’ve ever had a problem switching was the first time after we bought the house, about 15 years ago. Mainly because our original supplier had changed the meter but not updated any records so the readings were wildly inaccurate at the changeover.
Luckily I worked for said supplier at the time. My job being to sort out disputed meter reads when people switched suppliers. Which was handy…. 🙄