When and As soon as

Question: Is it better to say I’ll do it when I can or I’ll do it as soon as I can?

Grammar: Adverbs (time expressions)

The adverbs when and as soon as have roughly the same meaning, but not exactly the same.

Consider the following situations:

"I’ll finish my homework when I get home." The speaker gets home at 4:00pm.

He does his homework between 4:00 and his bedtime.

"I’ll finish my homework as soon as I get home."

The speaker gets home at 4:00pm. He works on his homework immediately, and finishes soon after.

What is the difference between these sentences?

I’ll buy an umbrella when the rainy season starts.

I’ll buy an umbrella as soon as the rainy season starts.

In the first sentence, the speaker may buy the umbrella a day or even a week after the first rain, but in the second sentence, it sounds like he will buy the umbrella a few minutes after the first rain. To answer the question above, it is probably more polite to say I’ll do it as soon as I can because this shows that you consider it important enough not to wait.