Тебе стоит перепроверить адрес перед отправкой письма.

Because the pattern кому-то стоит + infinitive uses the dative case.

So тебе стоит перепроверить адрес literally means something like:

• To you, it is worth rechecking the address
• more naturally: You should recheck the address

In Russian, this recommendation structure does not use ты стоит. It uses the person in the dative:

• мне стоит — I should
• тебе стоит — you should
• ему стоит — he should
• нам стоит — we should

Here, стоит does not mean costs.

It comes from стоить, and in this pattern it means:

• it is worth
• it would be a good idea
• should

So:

• Тебе стоит перепроверить адрес = You should / It would be a good idea for you to recheck the address

This is a fairly mild, natural recommendation. It is usually softer than a direct command.

Перепроверить means to check again, to double-check, or to recheck.

The prefix пере- often adds the idea of:

• doing something again
• redoing something
• repeating an action

Compare:

• проверить — to check
• перепроверить — to check again / double-check

So this sentence specifically suggests an extra check before sending the letter.

Because after стоит, Russian normally uses an infinitive.

The pattern is:

• кому-то стоит + infinitive

Examples:

• Тебе стоит подождать. — You should wait.
• Нам стоит уйти. — We should leave.
• Ей стоит позвонить. — She should call.

So перепроверить is in the infinitive because it is the action being recommended.

Адрес is the direct object of перепроверить, so it is in the accusative case.

But for many inanimate masculine singular nouns, the accusative looks exactly like the nominative.

So:

• nominative: адрес
• accusative: адрес

That is why there is no visible change.

Compare with a feminine noun, where the accusative often looks different:

• проверить карту — to check the map

After the preposition перед in this meaning of before, Russian uses the instrumental case.

So:

• отправка — nominative
• перед отправкой — instrumental

That is why отправка becomes отправкой.

The phrase перед отправкой письма means before sending the letter or more literally before the sending of the letter.

Because prepositions like перед are often followed by a noun phrase, not directly by an infinitive.

So Russian commonly says:

• перед отправкой письма — before sending the letter

using the verbal noun отправка.

A very common alternative with a verb is:

• перед тем, как отправить письмо

That also means before sending the letter.

So both are possible, but the version in your sentence is more compact and noun-based.

Because письма depends on the noun отправка.

The idea is:

• отправка чего? — sending of what?
• письма — of the letter

That is the genitive case.

So:

• отправка письма = the sending of the letter
• перед отправкой письма = before the sending of the letter / before sending the letter

This is very common in Russian: a verbal noun takes its object in the genitive.

Yes. That is a very natural alternative.

Compare:

• Тебе стоит перепроверить адрес перед отправкой письма.
• Тебе стоит перепроверить адрес перед тем, как отправить письмо.

Both mean essentially the same thing.

The difference is mostly stylistic:

• перед отправкой письма is more compact and slightly more formal/written
• перед тем, как отправить письмо feels a bit more conversational and verb-based

Yes, перепроверить is perfective.

In this sentence, the perfective aspect fits because the speaker recommends one complete action:

• double-check the address before sending the letter

If you used the imperfective перепроверять, it would usually suggest repeated or habitual action, which does not fit as well here.

So:

• перепроверить = do the check once, completely
• перепроверять = be rechecking repeatedly / as a habit / in general contexts

For a single recommended action before a specific event, perfective is the normal choice.

Yes. The person involved is expressed by тебе, but there is no normal nominative subject like ты.

This is an impersonal-style recommendation structure:

• Тебе стоит... — You should...
• literally: For you, it is worth...

So the sentence does not work like a standard ты + verb sentence. The recommendation is built around стоит plus the dative pronoun.

Yes, Russian word order is flexible, although the original order is very natural.

Original:

• Тебе стоит перепроверить адрес перед отправкой письма.

Possible variations:

• Перед отправкой письма тебе стоит перепроверить адрес.
• Адрес тебе стоит перепроверить перед отправкой письма.

These all work, but they shift emphasis:

• putting перед отправкой письма first emphasizes the time frame
• putting адрес earlier emphasizes the thing that should be checked

The original version is a neutral, natural order.

You would use вам instead of тебе:

• Вам стоит перепроверить адрес перед отправкой письма.

This can mean:

• You all should double-check the address before sending the letter
• or formal singular You should double-check the address before sending the letter

So:

• тебе = informal singular you
• вам = plural or formal singular you