You: Hey, I’m not sure when to use “will” and “should” in this sentence about runners buying new shoes.

Me: No problem! Let me break it down for you in a simple way.

When Do We Use "Will"?

Think about it like this—if we say, "Most runners will buy new shoes after 350 kilometers," we’re saying this is what usually happens.

• It’s like making a prediction based on what we’ve seen before.
• Runners don’t have to buy new shoes at 350 km, but most of them do because their shoes start wearing out.
• So when we say "will," we mean it’s pretty certain that runners are likely to do this.

What About "Should"?

Now, if we say, "Most runners should buy new shoes after 350 kilometers," we’re not saying they will do it, we’re just saying it’s a good idea for them to do it.

• Maybe some runners won’t change their shoes, but they should because old shoes can cause injuries.
• So "should" is more like advice, not a fact about what will happen.

Final Sentences in a Natural Way:

• "Most runners will buy new shoes after 350 kilometers." (Because that’s what usually happens.)
• "Most runners should buy new shoes after 350 kilometers." (Because it’s the smart thing to do.)

You: Oh, I get it now! "Will" is when we’re pretty sure something will happen, and "should" is when we’re just saying it’s a good choice.

Me: Exactly! You got it!