To ensure I don't overflow my pension in future, I require some way of best-guessing what the pension pot limit will be when I retire (it's currently £1.25M, soon to be £1M due to new policy).
Assuming I can withdraw from age 55 in the future, I will need to project forward 27 years from now (I am currently 28 years old).
Let's assume I can contribute the maximum of £40K each year.
Assuming the limit remained at £1M, and assuming an annualised market return of 9%, I would only need to make 3 years of contributions (£120K) to breach the £1M limit by retirement age - which would result in taxation on the difference (and hence poor financial planning in hindsight!).
However, it seems unlikely this limit will be £1M in 2043. One assumption would be a limit closer to £2M, given an estimated 3% annualised inflation.
How should I calculate when to stop contributing to my pension? (For example, is projecting a future pension pot limit based on inflation sensible?)