Yes I agree with @onlyfoolsnmothers
Certain outgoings are non negotiable and cannot be reduced...council tax, cost of trains if commuting, childcare Tec
So let's say you take home £2500 after tax
Mortgage/rent can easily be over £1000 in zone three London for a very modest home.
Council tax is over £100 a month usually...mine is £130
Travel into London..easily £150 a month
Utilities...gas, water, electric...easily £150 a month in cold weather
Broadband, tv license, mobile phone...£40 if you shop around
Then let's say you have children...my ds goes to a bog standard state school...he spends £65 a month on lunch roughly
My dd is in primary school...school lunches are about £55 a month
Now perhaps you have a car.. car insurance monthly is £50...plus petrol at £20 a week.
Now food...easily £70 a week even if budget shopping
We haven't even considered childcare for very young children in these calculations.
Then what happens when your dc needs a new coat...New school shoes...or there's a school trip. Both my dc have residential school trips this year totalling £400...ok, that may be a choice, but virtually every child is going and I don't want them to be left out.
Yes, you'll get by but you'll be panicking if your washing machine breaks or your boiler fails.