This is one of those 'how much does it cost to be middle class?' or 'how much does it cost to give my kids the same upbringing i had' threads that crop up on MN now and then, and to which I'm drawn like a moth to a flame because I work with demographics.
People always live right up to the brink, whether they're on £15k or £150k. Essential lifestyle accoutrements accumulate along with the extra income. You'll suddenly decide you need a bigger house or private school or a better-performing pension, and the extra won't last long.
If you're at the very start of your career, here are the things I wish I had known:
*Buy a place as soon as you can. Renting is very convenient whilst your career is in flux, but your career will never flourish whilst your living arrangements are insecure. Moving house at the behest of your landlord is very destabilising and in parts of the SE it can happen every year. If you can't afford a place where you work, buy a place you can afford somewhere you can see yourself living one day, and rent it out. It's just important to have that bedrock of security.
*Don't socialise with people whose lifestyle is subsidised by their parents. If they own their house outright and yours is on a mortgage, you may have the means to pay for the same holidays and eat at the same restaurants, but you can't really afford it in the same way.
*Investment dressing is a con: you don't need expensive clothes, and the latest bags, shoes and cosmetics to make a good impression in the workplace.
*All technology is a con. Buy the cheapest you can manage with, and use it until it breaks.
*All cars are a con, ditto.
*Save as much as you can in ISAs, premium bonds, pensions. Save before you spend, not what's left over.
*Don't pay off your student loan early.
*Don't have a fancy wedding.
I am very lucky to be financially secure and be having the exact lifestyle I would like, but if I hadn't made some many daft decisions in my early career I think I'd be positively rich by now.