Hon loggar alltid ut när hon har skrivit sitt inlägg, för säkerhets skull.

Because logga ut is a particle verb, like English log out. In Swedish, the finite verb often stays in the normal verb position, while the particle comes later:

• Hon loggar alltid ut
• literally: She logs always out

This is very common with Swedish particle verbs:

• stänger av = turns off
• går upp = gets up
• skriver ner = writes down

If you use the infinitive, the parts stay together more clearly:

• att logga ut = to log out

In a normal Swedish main clause, the finite verb usually comes early, and adverbs like alltid, ofta, inte, and nog often come after that verb.

So:

• Hon loggar alltid ut

not:

• Hon alltid loggar ut

This is a basic Swedish word-order pattern. English often allows She always logs out, but Swedish prefers subject + verb + adverb in this kind of sentence.

Har skrivit is the present perfect, and here it means after she has finished writing the post.

So the sentence is not just saying that she logs out while writing, but specifically once the writing is completed.

Compare:

• när hon skriver sitt inlägg = when she is writing her post / when she writes her post
• när hon har skrivit sitt inlägg = when she has written her post

In this sentence, the perfect form helps show completion before logging out.

Swedish uses the perfect quite naturally in time clauses when one action is completed before another.

Here the sequence is:

1. she writes the post
2. then she logs out

So när hon har skrivit sitt inlägg emphasizes that the writing is already done before the logout happens.

This is very idiomatic Swedish and not unusual at all.

Because sitt is the reflexive possessive, used when the possessor is the same as the subject of the clause.

Here, the subject is hon, and the post belongs to her, so Swedish uses sitt:

• Hon har skrivit sitt inlägg = She has written her own post

If you said hennes inlägg, it would usually mean someone else’s post, belonging to another woman.

Compare:

• Hon skrev sitt inlägg. = She wrote her own post.
• Hon skrev hennes inlägg. = She wrote her post, meaning another woman’s post.

The form depends on the gender and number of the noun being possessed:

• sin for common-gender singular nouns
• sitt for neuter singular nouns
• sina for plural nouns

Inlägg is a neuter noun:

• ett inlägg

So the correct reflexive possessive is:

• sitt inlägg

Examples:

• sin bok = her/his own book
• sitt hus = her/his own house
• sina vänner = her/his own friends

Inlägg is a very common Swedish word for a post, especially online: a forum post, social media post, blog post, comment-style contribution, and so on.

It can also mean an insert or contribution in other contexts, but here it clearly means an online written post.

So skrivit sitt inlägg means she has written her post.

Because Swedish needs an explicit subject in the subordinate clause too.

So:

• Hon loggar alltid ut = main clause
• när hon har skrivit sitt inlägg = subordinate clause

You cannot leave out the second hon the way English sometimes shortens things informally. Swedish normally keeps the subject stated clearly.

Because när hon har skrivit sitt inlägg is a subordinate clause, and Swedish subordinate clauses do not use the same word order as questions.

• när hon har skrivit ... = when she has written ...
• När har hon skrivit ...? = When has she written ...?

In the sentence you gave, när means when, introducing a time clause, not a question.

Yes, it is a very common fixed expression meaning:

• just to be safe
• as a precaution
• for safety’s sake

Literally, skull is an old noun that survives in expressions like this. You do not usually analyze it word by word in everyday learning; it is best learned as a whole phrase:

• för säkerhets skull

Other examples:

• Ta med ett paraply för säkerhets skull. = Bring an umbrella just to be safe.
• Jag dubbelkollar för säkerhets skull. = I double-check just in case.

Not always. In Swedish, commas are often used more lightly than in English, and this comma is mostly there to separate off the final extra comment-like phrase.

So both of these can be seen:

• Hon loggar alltid ut när hon har skrivit sitt inlägg, för säkerhets skull.
• Hon loggar alltid ut när hon har skrivit sitt inlägg för säkerhets skull.

The version with the comma makes för säkerhets skull feel a little more like an added explanation: as a precaution.

Yes. It is a very normal modern Swedish verb, borrowed from English and adapted to Swedish grammar.

You can conjugate it like other Swedish verbs:

• logga ut = infinitive
• loggar ut = present
• loggade ut = past
• har loggat ut = present perfect

This is common with technology words in Swedish.

Grammatically, Swedish does allow other elements first because of the V2 rule, but Alltid loggar hon ut... sounds marked or literary in this context.

The normal neutral order is:

• Hon loggar alltid ut ...

If you move something to the front, the verb must still stay in second position:

• När hon har skrivit sitt inlägg loggar hon alltid ut.

That sentence is also correct, but it puts more focus on the time clause.

Because the sentence is talking about her action of writing, not the state of the post.

• har skrivit = has written
• active: she did the writing

A passive or adjective-like form would shift the meaning toward the post being written, rather than her having completed the action. Swedish, like English, normally uses the active perfect here.

Yes, in terms of meaning, that is often a very good way to understand it.

• när hon har skrivit sitt inlägg
  can feel like
• once she has written her post

So although när usually means when, in this kind of context it can imply after/as soon as/once the action is complete.