Maybe I should have explain it better.
You don't do it forever, like I said in my post, eventually you slow down hitting your tax allowance band.Let me detail how I did it.
I eventually let compounding assist me.
When I started earning 25k after I graduated. It think took me about 6 years to get to my first 90k. I paid in nearly all my taxable income to my pension, I did have and extra £50 or so a month over my taxe free allowance.
Then compound interest took over and I reduced my wage funding by the interest.
A few years later I stopped working, 6 years I bummed around.
My pension was already contributing around 5k plus a year on its own.
I started to work again earning 30k, now I reduced my direct funding by my interest per year so my take home pay was about 18k. I did that for a few years the more I earned the less I funded directly. I made sure that the pension growth and wage would combine would be the difference between tax free and rest of my income.
My wage was growing by my interest in my pension. You might say I wasn't using all my allowance, but for good reason. Sure you can picture it now.
I took another few years off, pension still grew.
Then I went back to work.
Eventually I had to change tactics.
My pension was growing faster than I would have thought and my income as well.
Now Iam putting in only higher tax earnings a bit of my lower tax earnings ( gradually this is less and less as income grows but banding does not). This takes In to account my fiscal drag.
I am bit annoyed they aren't going to increase the bands until 28.
By doing it this way I don't get mugged if I have savings over the allowed rate if I need to sign on, if I lose my job. My savings account is my pension.
The idea was, get to 54 extract my 25% and buy a place abroad outright and retire. Rent out our place and spilt the rent, or use the other portion of the pension allowance that is still available to put the surplus rent into. This was one option.
We purchased a house together using my lower rate of tax and her wage, advance inheritance from her side.
I used goal seek to optimise my funding strategy.
So you don't live the whole 20 years on your base.
You take into account your portion of yearly pension growth and wage.
The first years off fully funding my pension provide me with a bloody great base and start.