As far as your situation is concerned, it is better to pay the same amount of principal and interest every month. In fact, there is a misunderstanding that the average capital is cost-effective. In fact, at the beginning, the repayment amount in the average capital was one third higher than the equivalent principal and interest. In this way, the present money is always more valuable than the future money. Besides, you can't just pay interest for 30 years. Then you gave it all to the bank from the beginning, which is actually a personal loss. So I suggest equal principal and interest every month, because interest and principal are equally divided.