To wonder if it’s really true that you should avoid discussing money with anyone other than those directly involved with your finances?

Why would you talk money with anyone at all? Its vulgar.

In reply to money...politics...religion.

As previous posters have said, it depends on the circumstances and is down to your judgement.

Personally I have been burned badly and am really careful now about giving any clues as to how much we do or don’t have, even with close family. In the past, several family members have taken advantage of us and in hindsight that’s partly our fault for being too open. I’ve also had an acquaintance try to use us for money when she thought we were worth a far bit (even though we weren’t) and whilst she didn’t get very far it has stuck with me to just never engage in talking about money with anyone outside my household.

I'm a multi billionnaire anarchist druid but you'd never know it to look at me.

Way too broad a question, depends entirely on what you mean by 'discussing finances' and with whom. World of difference between sharing the exact amount that's in your pension pot, ISAs and equity in your house with a school - run acquaintance than comparing notes on cost of living anxieties or what you think of the budget with your sister or best friend. Not saying either is wrong per se but the former obviously has a lot more potential to be over-sharing or generate strong feelings than the latter.

Personally anything to do with money is something I'd steer clear on at work or with casual acquaintances, it's just too personal - even if you aren't sharing or asking for personal financial details, just talking in general about the budget say, or your thoughts on the welfare state just has the potential to offend or upset, you just never know what people have going on and there are so many other more neutral topics to talk about with people you don't know well. With close friends and family I would talk money perhaps more generally, it's a stereotypical but sadly true trope of middle class dinner parties to bang on about mortgage rates, house prices, pensions and so on, it's not my favourite topic but I join in for politeness. I certainly wouldn't be sharing personal details like how much mortgage is or what my pension arrangements are except with very close friends and family though?

Also depends on the circumstances.

If someone’s looking to have a loft conversion done it’s perfectly ok to say yours cost £££. But you wouldn’t, in most circumstances, randomly mention at a meal out your loft conversion cost £££ unless you were trying to brag.

Money, religion, and politics.
Always be careful.

Discussing money, like any sensitive topic, can be done with anyone you like. However, it is a sensitive topic so you need to understand that discussing it may lead to judgement, bad feelings, or other unwanted scenarios. I have friends with whom I can be quite open and honest about finances. There are lots of people I would not discuss finances with in any shape or form.