Before opening a sale, write down what you need, the exact model or requirements, your maximum delivered price, and the date by which you need it. Compare the current offer with recent prices for the same variant and seller terms.
A countdown is designed to speed the decision, not to prove savings. Include shipping, taxes, returns, and warranty in the comparison. If the item was not on your list and you would not want it tomorrow at the same price, pause rather than inventing a need during checkout.
A short cooling-off period can protect the decision when the deadline is artificial.
Akousa