You cannot save time; you can only decide what receives it.

There is no way to store time. The idea of saving it is a misunderstanding, since every efficiency simply frees the hour to go somewhere else, and it usually goes somewhere by default. The only real decision is allocation. Which means the productivity question is less about speed and more about what you are making room for.

When you save time on something, decide immediately where the saved hour goes rather than letting it be absorbed. Name the recipient in advance. Otherwise the efficiency just quietly increases the amount you do without changing what you do.