[viseztrance]

> Debt repayment has one vital characteristic: it is easy to understand

If it were this easy you wouldn't see so many people taking on so many unnecessary debts. Technical or otherwise.

[Tade0]

I'm in the process of searching for an apartment to buy and the formula for calculating the installment amount, while using only basic operations, is anything but simple.

Chiefly the answer to the question "how will this amount change if the interest rates go from effectively zero to 6%, which is the 30-year average?" is not straightforward.