不繳納養老保險，銀行每月存900元，30年後可達40萬以上。

If I choose not to pay pension insurance, but save 900 yuan per month in the bank, the cumulative amount in a year will be 10,800 yuan. After 30 years of accumulation, the principal will reach 324,000 yuan. During these 30 years, assuming that the bank's annual interest rate has been maintained at 3%, the annual interest income is: 1.08×300×(1+2+…+30)=90,480 yuan. Adding up the principal and interest, the total amount is approximately more than 400,000 yuan. By the time I retire at age 60, I expect I may have more than $400,000. But to consider whether this money is enough for retirement, I must carefully weigh which option is more cost-effective compared with paying pension insurance.