To think that more friendships have been ruined because of money than anything else?

Not in my experience, no. I've never lent money to friends though (beyond a tenner for a few drinks or something).

If I become aware that a friend is tightfisted, I tend to clarify who is paying for what upfront, and don't give them the opportunity to take the piss.

E.g. I'm not afraid of saying outright that I am only going to pay for what I ordered in a restaurant because I didn't have any booze and only had a starter while others had steak. I also make sure I pay my fair share when I order the pricier menu options too - it goes both ways.

I'm always shocked when I read threads on MN where the OP has somehow paid for everything for years because they are too afraid of conflict to insist on fairly splitting restaurant bills, or ask for petrol money from their 'friend'.

Not in my experience. In my experience friendships end because someone feels the friendship is unequal. That can present as money e.g always paying for something but when someone evaluates that friendship they will realise it goes beyond money to emotional and practical support too.

It hasn’t for me personally, although I do sense some tension within a group of four old friends. Due to her life choices, one of us has more limited funds and I do sense some envy when one friend in particular goes on holiday, for example. But the less well off friend chose to have more children and be a SAHM so it was inevitable that she’d have less money than the more affluent friend (who is quite senior in her field). They chose different paths in life, that’s all.

I have some friends who have trust funds and are in an entirely different financial league to me. I’m honest with them if I can’t go a certain activity or eat at an expensive restaurant, for example. No point being envious, it’s not going to change anything!