In the US it's a gamble based on the actuarial tables. File earlier and get a reduced amount for longer or wait and get a greater amount for what statistically will be a shorter period. The full benefit is paid at
66, reduced benefits at the minimum enrollment age of 62, and increased benefits at 8% per year if you delay past 66 up to 70. Inflation also enters into it but the break even age is somewhere around 85.You do get your pension and salary but the pension is taxable up to 85%. It turns into a real accountant's game plus rolling the dice on how long you personally will live versus the actuarial tables. If you're sickly, grab the money at 62 and run.