In the UK we have Universal Credit. A family in my specific circumstances (2 adults, 2 kids, 1 income, renting) will receive some until you reach a single income of around £77,000/year.
They work out your total entitlement (around £2,100 for me) and then 55% of 'take-home pay' comes off of that.
So:
35k salary = £900 deductions (tax etc) and £2,000 take-home. They take £1,100 from entitlement and you receive £1,000 payment.
50k salary = £1,500 deductions (tax etc) and £2,707 take-home. They take £1,489 from entitlement and you receive £611 payment.
65k salary = £2,157 deductions (tax etc) and £3,260 take-home. They take £1,793 from entitlement and you receive £307 payment.
I was on 50k and had £3,351 hitting my bank every month. I had a lot of things getting to me and I was considering moving to a new job. That's what led me to work this all out.
I could have got my earnings up to £65k if I was committed. I discovered that at 65k, £3,556 would hit my bank account which was not enough of a difference to improve my life overall… After some months of contemplation I decided to go in the opposite direction.
I now earn 35k in a lower stress job, working 4 days per week. £3,101 hits my bank account per month.
Being £250/mo worse-off has certainly increased some financial strains but it's resulted in massive leaps of improvement in all other areas of life. Before making the change, I was struggling in so many ways and now my only struggle is financial (and even then, we're basically ok).
I'm not criticising how the UK does it. It sort of guarantees that everyone (on the lower rungs anyway) ends up with a similar amount and that everyone has enough. It has absolutely destroyed any motivation I once had to achieve more though, and I always turn down overtime where possible.
This spreadsheet shows how each salary would work for me. There has been very minor changes to the calculations since I created it.