Advice to young people: somehow magically have the right combination of job, accommodation, utility services and local government such that putting away half of your take-home salary as savings isn't an absurd pipe-dream!

My salary after tax and other deductions is ~£1080 per calendar month.
Rent: £340
Council tax: £72
Water: £32
Electricity: £45
Internet: £20
A total of £509

I have barely half my take-home salary left after paying the bills. And that's before considering the fact that I need to, y'know, eat. Let's say my grocery bills come to £40 per week; that's probably conservative, but I guess for the sake of this exercise I'm cutting back a little without going full ramen. Add another £160 to the bills. Call it £161 for the convenience:
£670

So I've got £410 left. Less than half already. I guess, if I have literally no indulgences at all I might be able to manage almost half of my salary as savings. And I'll note that our rent is cheap for our town; we live in a place where you can't take a fucking bath because it comes through the kitchen ceiling.

Your advice is very good for people who live in magic fantasy land; less so for people who live in reality.