אני תמיד מכבה את האור לפני שאני יוצא מהבית.

Because האור is a definite direct object: the light.

In Hebrew, when a verb takes a direct object that is definite, you usually put את before it.

• אני מכבה אור = I turn off a light
• אני מכבה את האור = I turn off the light

Important: in this sentence, את is not the word with. It is just a grammatical marker showing that האור is the specific thing being turned off.

In Hebrew, the normal verb for turning off a light or electrical device is לכבות.

So:

• לכבות את האור = to turn off the light
• להדליק את האור = to turn on the light

Hebrew uses the idea of extinguishing here, not the English phrasal verb turn off.

Because Hebrew present tense often covers what English calls the simple present, especially for habits and routines.

So:

• אני תמיד מכבה את האור literally looks like I am always turning off the light
• but in normal English it means I always turn off the light

This is very common in Hebrew. The present tense form is used for:

• general facts
• habits
• repeated actions

Since תמיד means always, the habitual meaning is clear.

That is a very natural Hebrew word order:

• אני תמיד מכבה את האור

Literally: I always turn off the light

Hebrew adverbs like תמיד are fairly flexible, but this position is very common and natural.
Other placements may be possible depending on emphasis, but אני תמיד מכבה... is the standard, neutral phrasing.

Because in Hebrew, after לפני (before), it is very common to use a full clause:

• לפני שאני יוצא = before I go out / before I leave

English often uses before leaving, but Hebrew usually prefers:

• לפני שאני יוצא
• literally: before that I leave

A more noun-like alternative is possible, such as:

• לפני היציאה מהבית = before leaving the house / before the exit from the house

But לפני שאני יוצא מהבית is the most natural everyday version.

The ש is a shortened form of אשר and often works like that, although in many cases it is not translated directly into English.

So:

• לפני שאני יוצא
  literally: before that I leave

In natural English, we just say:

• before I leave

So the ש introduces the subordinate clause.

Also notice that שאני is really:

• ש + אני = that + I

written together.

Because לפני שאני יוצא מהבית is its own clause, and that clause needs its own subject.

So the sentence has two parts:

1. אני תמיד מכבה את האור
2. לפני שאני יוצא מהבית

In the second part, Hebrew explicitly says אני again:

• before I leave the house

That is completely normal. English does the same thing too:
I always turn off the light before I leave the house.

Because לצאת means to go out / to leave, which fits מהבית very naturally:

• יוצא מהבית = leave the house / go out of the house

If you used הולך, that would mean go / walk, which is a different idea.

So:

• אני יוצא מהבית = I leave the house / I go out of the house
• אני הולך הביתה = I am going home

Here, יוצא is the right verb for leaving.

Because מהבית combines the preposition מ־ (from) with הבית (the house).

So:

• מ־ = from
• הבית = the house
• מהבית = from the house

This is very common in Hebrew. Prepositions are often attached directly to the following word.

So:

• מהבית = from the house
• לבית = to a house
• לביתו = to his house

In this sentence, מהבית means from the house / out of the house.

Because ה־ is the Hebrew definite article, meaning the.

So:

• אור = light
• האור = the light

and

• בית = house
• הבית = the house

Since the sentence refers to specific things, Hebrew uses the definite article in both places.

Hebrew present-tense verbs agree with the subject in gender and number.

So if a man is speaking:

• אני יוצא מהבית = I leave the house

If a woman is speaking:

• אני יוצאת מהבית

In this sentence, יוצא shows a masculine singular speaker.

Also, the first verb may change in spoken explanation depending on gender, but here there is an interesting detail: מכבה is written the same way for masculine and feminine singular in ordinary spelling, though the pronunciation/stress differs.

So a woman would typically say:

• אני תמיד מכבה את האור לפני שאני יוצאת מהבית

The visible difference is especially clear in יוצאת.

Yes. The verb מכבה comes from the root כ־ב־ה, which has to do with going out or being extinguished.

A useful comparison is:

• האור כבה = the light went out
• אני מכבה את האור = I turn off the light

So:

• כבה = go out / be extinguished
• כיבה / מכבה = extinguish / turn off

This is a helpful pattern in Hebrew: sometimes one form describes something happening by itself, and another form describes causing it to happen.

Yes. יוצא מהבית can be understood as:

• leave the house
• go out of the house

Both are natural translations. English chooses whichever sounds better in context.

So the Hebrew phrase is a little broader than just one fixed English wording.

Yes, very natural.

It sounds like normal spoken or written Hebrew:

• אני תמיד מכבה את האור לפני שאני יוצא מהבית.

It uses common everyday structures:

• אני תמיד... for a habit
• מכבה את האור for turning off the light
• לפני שאני... for before I...
• יוצא מהבית for leaving the house

So this is a very good model sentence for everyday Hebrew.