You aren't very good at this….Energy is a laughable example in a price capped market. Car insurance again is a poor example as the market is littered with provides who’s whole business is based on luring you in with a deceptively cheap price via comparison site, then finding a trivial reason to increase it and charge vastly more resulting in a cancelation fee or amendment fee and increased premium. I tend to stick to the same individual who deals with my insurance, shes good at her job, happy to assist me with some pretty non standard stuff and mirrors my NCB over multiple policies. That alone is worth 10x what she makes on my business and instead of worrying about saving £5/m, I just get on with life and enjoy it.
I cant imagine a world where saving £5/m is worth this much of your time, clearly you can. Good luck with that