From a current income tax perspective only, social security benefits are preferable to 403(b) distributions because, at most, only 85% of social security benefits are taxed at the Federal level and not taxed at all in many states. However, the tax implications are probably not the most important factor to consider. Other important factors to consider are your life expectancy (hopefully an unknown), the rate of return on your investments inside the 403(b) plan and outside the 403(b) plan (if any), the impact on your spousal benefit (will be less than 50% if you claim before full retirement age), between age 64 and 67 monthly benefit increases 5/9 of 1% each month, if you are forced back into the workforce your monthly SS benefits will be greatly reduced if you exceed the annual income limit ($1 for every $2 above $22,300 in 2024). Not an easy decision.