This will depend on how you use the money in your pension pot. Other things that will affect how long it lasts are - how old you are when you reduce your hours or stop working and your life expectancy.
If you decide to use some of your pension money to pay off your mortgage or go on a big holiday, it will mean there is less to use for an income so you will either need to reduce your income or it won’t last as long.
For more information visit Pension Wise Make your money last.