I had an RAC call out after a garage botched a service a few years ago (my usual luck). I was chatting afterwards about changing a tyre in a layby the last time and got pointed out: why do it. Paying for RAC to do it so why do it yourself? Must admit I never really thought about it, everyone should know how to do it -if you can you do it naturally. Thinking twice he was maybe right , certainly if there was any risk involved and of course not everyone is physically capable. I've never been convinced about the orange triangle thing but I carry high vis, spare shoes, warm jackets, torch, first aid kit etc if I ever have a breakdown or stop at an accident. I'm not sure I'd be happy with a flare or see much point. Having had lots of JDM cars they're already removed at importing, and not sure I'd be happy carrying one. I've always donned my high vis if I've had troubles (there's been a few), but suppose that's a carry over from too much HSE involvement over the years!
Someone I know was brutally killed fixing a tyre on the A9 by a Morrisons truck driver texting at the time. I'm told that led to the push for the A9 average cameras. I think they're a total con. I'm still overtaken by folk doing a ton then stuck behind them at 40 in a 60 for a few miles to balance it out. Bikers are the worst for it.