waipaireul an sseumyeon hyudaepon baeteoriga deo orae gayo.

-(으)면 means if or when.

So:

• 안 쓰면 = if you don't use it
• 와이파이를 안 쓰면 = if you don't use Wi-Fi

In this sentence, it sets up a condition: if you don't use Wi-Fi, then the phone battery lasts longer.

With 쓰다, the stem ends in a vowel, so you use -면:

• 쓰다 → 쓰면

-을/를 is the object marker. It marks the thing being used.

Here:

• 와이파이 = Wi-Fi
• 와이파이를 쓰다 = to use Wi-Fi

So in 와이파이를 안 쓰면, Wi-Fi is the object of 쓰다.

A native English speaker may wonder why English has no equivalent word here. In Korean, object markers are very common and help show what the verb is acting on.

Both are possible, but 쓰다 is much more natural and common in everyday speech for to use.

• 쓰다 = use
• 사용하다 = use, utilize

So:

• 와이파이를 안 쓰면 sounds natural and conversational.
• 와이파이를 사용하지 않으면 is grammatically correct, but more formal or stiff in ordinary conversation.

Korean often prefers shorter, more everyday verbs in speech.

안 is a simple way to make a verb negative.

• 쓰다 = to use
• 안 쓰다 = to not use

So:

• 와이파이를 안 쓰면 = if you don't use Wi-Fi

This is the everyday negative form. Another way is:

• 쓰지 않으면

That means the same thing, but 안 쓰면 is shorter and very common in speech.

-이/가 is the subject marker.

In this sentence, the thing that lasts longer is the phone battery, so that whole noun phrase is the subject:

• 휴대폰 배터리 = phone battery
• 휴대폰 배터리가 = the phone battery

So the structure is basically:

• If you don't use Wi-Fi, the phone battery lasts longer.

The battery is not the object here; it is the thing doing the action of 오래 가다.

Because the thing that lasts is the battery, not the phone itself.

• 휴대폰 = mobile phone / cell phone
• 배터리 = battery
• 휴대폰 배터리 = phone battery

Korean often puts nouns together like this, similar to English noun compounds.

So:

• 휴대폰이 더 오래 가요 could mean the phone lasts longer
• 휴대폰 배터리가 더 오래 가요 specifically means the phone battery lasts longer

The version with 배터리 is more precise.

더 means more.

Here it makes a comparison:

• 오래 가요 = lasts a long time
• 더 오래 가요 = lasts longer

The comparison is understood from context: longer than if you use Wi-Fi.

Korean often uses 더 without stating both sides of the comparison explicitly.

Yes, 가다 usually means to go, but in the expression 오래 가다, it means to last.

This is a very common expression:

• 오래 가다 = to last a long time
• 배터리가 오래 가다 = the battery lasts a long time

So in this sentence:

• 더 오래 가요 = lasts longer

This is one of those cases where a very common verb has an idiomatic meaning in a certain expression.

Because 오래 가다 is the natural fixed expression for to last a long time.

• 오래 = for a long time / long
• 오래 가다 = to last long

Even though 길다 means to be long, Korean does not usually say 길게 가다 for battery life.

So learners should remember 오래 가다 as a set phrase.

Examples:

• 이 배터리는 오래 가요. = This battery lasts a long time.
• 충전이 오래 가요. = The charge lasts a long time.

가요 is the polite present tense form of 가다.

• dictionary form: 가다
• polite style: 가요

This is the standard polite conversational style, very common in speech and everyday writing.

So the sentence sounds natural and polite without being overly formal.

Compare:

• 가요 = polite, everyday
• 갑니다 = more formal
• 가 = casual/plain intimate style

Yes. These mean essentially the same thing:

• 와이파이를 안 쓰면
• 와이파이를 쓰지 않으면

Both mean if you don't use Wi-Fi.

The difference is mostly style:

• 안 쓰면 = shorter, more conversational
• 쓰지 않으면 = a little more formal or written

In everyday spoken Korean, 안 쓰면 is extremely common.

No. Korean also commonly uses 핸드폰 in speech.

• 휴대폰 = mobile phone, somewhat more neutral/standard
• 핸드폰 = cellphone, very common in everyday Korean

So you may also hear:

• 핸드폰 배터리가 더 오래 가요.

That would mean the same thing.

Yes. This sentence is already natural, but there are several other common ways to express the same idea.

For example:

• 와이파이를 끄면 배터리가 더 오래 가요.
  = If you turn off Wi-Fi, the battery lasts longer.

• 와이파이를 안 켜면 배터리가 더 오래 가요.
  = If you don't turn on Wi-Fi, the battery lasts longer.

• 와이파이를 안 쓰면 배터리 소모가 줄어요.
  = If you don't use Wi-Fi, battery consumption decreases.

Your original sentence is very normal and easy to understand. It focuses on not using Wi-Fi, while other versions may focus more specifically on turning it off.

Usually it sounds like a general fact or practical advice.

• 와이파이를 안 쓰면 = if you don't use Wi-Fi
• 휴대폰 배터리가 더 오래 가요 = the phone battery lasts longer

So it sounds like something you might say when giving advice about saving battery.

Depending on context, it could also refer to a specific phone, but without extra context, most people will understand it as a general statement.