How much money needs to be accumulated or saved for retirement?
This number is very variable as it depends on a number of factors
Where you live-cost of living
When do you retire?
What kind of life you want to lead after retirement
How long you will live?
Do you want to leave any money left for your kids?
What will be the inflation?
Will you have passive income?
Any inheritance that you will get etc.
Typically 25-30 times your expected annual expenditures during retirement