Tengo la manía de revisar el correo dos veces antes de dormir.

It means to have a habit / obsession / tendency to do something, often with the idea that it is a bit repetitive, fussy, or hard to stop.

So Tengo la manía de revisar el correo... is like saying:

• I have this habit of checking my email...
• I tend to check my email...
• I’m obsessed with checking my email... (stronger in English, so use with care)

In Spanish, manía can sound slightly negative or quirky, not always serious.

Because in this expression, Spanish normally uses the article:

• tener la manía de...

This is the standard pattern. Spanish often uses a definite article in places where English would not.

Compare:

• Tiene la costumbre de leer antes de dormir.
• Tengo la impresión de que...
• Tiene la manía de llegar tarde.

So la is not optional here in normal usage.

Because manía is followed by de + infinitive when you say what the habit or obsession is.

Pattern:

• tener la manía de + infinitive

Examples:

• Tiene la manía de morderse las uñas.
• Tengo la manía de ordenar todo.

So in your sentence:

• de revisar = of checking

Here revisar means to check, to go over, or to look through.

With el correo, it usually means:

• to check email
• to look through your mail/messages

It is very natural in Spanish.

Other possibilities exist, but they are not exactly the same:

• mirar el correo = look at/check the email
• comprobar el correo = check/verify the email, a bit less common here
• consultar el correo = consult/check your email, more formal

So revisar el correo sounds very normal.

It can mean either mail/post or email, depending on context.

In this sentence, most people will probably understand email, because:

• revisar el correo
• dos veces antes de dormir

sounds like checking your inbox.

If you want to make it completely clear, you could say:

• el correo electrónico = email

In everyday Spanish, though, el correo often already means email.

Spanish often uses the definite article where English would use a possessive.

So:

• revisar el correo

can naturally mean:

• check my email
• check the email

depending on context.

Since the subject is I, it is often obvious whose email we are talking about.

You could also say:

• Tengo la manía de revisar mi correo...

That is also correct, but el correo sounds very natural and less heavy.

Because dos veces already tells you the number of times, and the rest of the sentence gives the time frame:

• antes de dormir = before going to sleep

So the full idea is that the person checks it twice before sleeping.

If you said dos veces al día, that would mean twice a day, which is different.

Compare:

• Reviso el correo dos veces antes de dormir. = I check my email twice before going to sleep.
• Reviso el correo dos veces al día. = I check my email twice a day.

Because dormir can be used in a general sense: to sleep / to go to sleep.

So:

• antes de dormir = before sleeping / before going to sleep

Using dormirme would focus more specifically on falling asleep myself.

Both can be possible in some contexts, but antes de dormir is very common and natural.

You may also hear:

• antes de irme a dormir = before I go to bed / before I go to sleep

That is a bit more explicit.

Because Spanish often leaves out the subject pronoun when it is clear from the verb ending.

• Tengo already tells you it is I have

So:

• Tengo la manía de revisar el correo...

naturally means:

• I have the habit of checking my email...

You could say Yo tengo la manía..., but that would add emphasis, for example:

• Yo tengo la manía de revisar el correo; mi hermana no.

Often slightly, yes.

It can suggest:

• a quirky habit
• a fixation
• something a bit excessive
• something mildly annoying or irrational

So this sentence sounds a little like:

• I have this thing where I check my email twice before bed.

If you want something more neutral, you could say:

• Tengo la costumbre de revisar el correo... = I have the habit of checking my email...
• Suelo revisar el correo... = I usually check my email...

So manía adds personality and a small negative or obsessive nuance.

Normally, no. The usual expression is:

• tener la manía de + infinitive

So tengo la manía de... is the standard form.

Using una manía is possible in other contexts when you mean a particular obsession/quirk, but with this structure, la manía de is what sounds natural.

Yes, the word order is natural.

• Tengo la manía de revisar el correo dos veces antes de dormir.

Here dos veces naturally modifies revisar.

You can sometimes move it for emphasis, but the original version is the most straightforward. For example:

• Tengo la manía de revisar dos veces el correo antes de dormir.

This is also understandable, but many speakers would prefer the original sentence.

So for learners, the given order is a very good model.

Yes, it sounds natural in Spain.

A speaker from Spain might also say:

• Tengo la manía de mirar el correo dos veces antes de dormir.
• Tengo la costumbre de revisar el correo antes de acostarme.

But your original sentence is perfectly normal and idiomatic.