Johnson, aged 45, divorced last year and has two children, aged 10 and 8 respectively. His annual salary is HK$720,000 as a Credit Manager in a large finance company. Under the divorce settlement agreement, he must pay HK$18,000 a month to support childrens expenses and HK$5,000 a month in alimony to his ex-wife. She is earning HK$400,000 a year as a secretary in a local company. Johnson does not currently hold an apartment and is now renting an apartment, and the divorce settlement left him about $900,000 in savings and retirement benefits. His employer provides a $700,000 life insurance policy and his ex-wife is a beneficiary on this policy.

What factors should be considered by Johnson in deciding whether to buy additional life insurance at this point in his life?