Which birth control method is most suitable for a couple who has completed their family-planning goals?

The most suitable birth control method for a couple who has completed their family-planning goals is sterilization. This method is designed for individuals or couples who are certain that they do not want any more children. Sterilization is a permanent form of birth control, which can offer peace of mind and eliminate the ongoing need for contraceptive measures.

This method includes options such as tubal ligation for women, which involves blocking or sealing the fallopian tubes, and vasectomy for men, which involves cutting or sealing the vas deferens. Both procedures prevent sperm from fertilizing an egg, thus providing a highly effective means of preventing pregnancy.

Other methods like diaphragms, male condoms, and spermicides are more appropriate for those who may want to avoid pregnancy temporarily or plan to have children in the future. These methods require ongoing use and may not provide the lasting solution that a couple with completed family-planning goals would seek.