English: use properly, to use (various things) for different purposes, use (different things) according to one’s purpose
“使い分ける” is a word that does not have a literal translation in English, and the nuance might be hard to comprehend. 使う means “to use”, and 分ける means “divide”. 使い分ける means; you have multiple options (of tools or methods) and choose the one depending on the situation or usage.
Japanese people use Keigo and casual language properly according to the situation.
A: You have a lot of spice.
B: I use different one depending on the dish.