Há dias em que arrumar a casa parece impossível, sobretudo quando chegamos cansados do trabalho.

Yes, há dias can mean two different things depending on context:

• Há dias em que... = There are days when...
• Há dias on its own can also mean a few days ago

In this sentence, the structure há dias em que... clearly means there are days when... because it introduces a general situation.

So here há is not about the past; it is the impersonal verb haver meaning there is / there are.

In standard Portuguese, há is a very common way to say there is / there are.

• Há um problema. = There is a problem.
• Há dias em que... = There are days when...

A few useful notes:

• há is from haver
• in this existential use, it stays in the singular
• it does not change to match the noun after it

So you say:

• Há um dia...
• Há dias...

not hão dias

In informal spoken Portuguese, especially in some varieties, people may use tem in this sense, but há is the standard and safest choice in writing and careful speech.

Because em que is the normal relative structure after a noun like dias.

• dias em que = days when / days on which

Portuguese often uses em que where English simply uses when.

Examples:

• os momentos em que tudo muda = the moments when everything changes
• os dias em que chove = the days when it rains

Using quando directly after dias is not the usual structure here.
So há dias em que... is the natural expression.

Because the action itself is the subject of parece.

• Arrumar a casa parece impossível.
• literally: To tidy the house seems impossible.

In English, we often prefer Tidying the house seems impossible, using -ing.
Portuguese very naturally uses the infinitive in this kind of sentence.

Other examples:

• Estudar é importante. = Studying is important.
• Esperar custa muito. = Waiting is very hard.

So arrumar is not strange here at all; it is a very normal structure.

Because dias is not the subject of parece.

The subject is the whole action:

• arrumar a casa = tidying the house

So the core structure is:

• Arrumar a casa parece impossível.

Then há dias em que... is just the frame around it:

• There are days when tidying the house seems impossible

That is why the verb is singular: parece.

Not exactly.

Arrumar a casa usually means something like:

• tidy the house
• put the house in order
• straighten things up at home

It often suggests organising, putting things away, making the place neat.

If you specifically mean clean in the sense of washing, wiping, sweeping, etc., Portuguese often uses:

• limpar a casa = clean the house

So:

• arrumar = tidy / organise / put in order
• limpar = clean

In real life, arrumar a casa can sometimes feel broad enough to include general housework, but its core meaning is more tidy up than clean.

Because Portuguese often drops subject pronouns when the verb ending already makes the subject clear.

• chegamos already tells you the subject is nós = we

So:

• quando chegamos cansados do trabalho
• quando nós chegamos cansados do trabalho

Both are possible, but the first is more neutral and natural unless you want emphasis or contrast.

This is very common in Portuguese:

• Fui ao mercado. = I went to the market.
• Estamos cansados. = We are tired.

The pronoun is often unnecessary.

Here the present tense is used for a general, repeated situation.

The sentence means something like:

• There are days when tidying the house seems impossible, especially when we get home tired from work.

This is not talking about one specific day in the past. It is describing what usually happens.

So the present tense works well:

• quando chegamos cansados do trabalho = when we arrive/get home tired from work

If you were talking about one specific past occasion, you would use the past:

• quando chegámos cansados do trabalho = when we arrived home tired from work

In European Portuguese, the accent helps distinguish them in writing:

• chegamos = present
• chegámos = past

Cansados agrees with the implied subject nós.

Because the subject is we, the adjective must be plural:

• nós chegamos cansados = we arrive tired

As for gender:

• cansados = masculine plural, or a mixed group
• cansadas = feminine plural

So:

• if the speakers are all women: chegamos cansadas do trabalho
• if the group is mixed or unspecified: chegamos cansados do trabalho

This is standard adjective agreement in Portuguese.

Do is a contraction of:

• de + o = do

So:

• o trabalho = the work / the job
• do trabalho = from work / of work

In this sentence, do trabalho gives the source or context of the tiredness:

• cansados do trabalho = tired from work

It can also feel close to coming home from work tired, which is why English may translate it a bit flexibly.

Other contractions of this type:

• de + a = da
• em + o = no
• a + o = ao

These contractions are extremely common in Portuguese.

Sobretudo means:

• especially
• above all
• particularly

So it adds emphasis:

• ..., sobretudo quando chegamos cansados do trabalho.
• ..., especially when we get home tired from work.

It highlights the most important case.

Similar words include:

• principalmente
• especialmente

Sobretudo is very natural and slightly more formal or polished in tone than some alternatives, though it is still common.

Yes, absolutely.

Both of these are natural:

• Há dias em que arrumar a casa parece impossível.
• Há dias em que parece impossível arrumar a casa.

The meaning is basically the same.

The difference is mainly one of focus and rhythm:

• arrumar a casa parece impossível puts the action arrumar a casa slightly more upfront
• parece impossível arrumar a casa puts parece impossível first, so the feeling of impossibility comes earlier

Both are good Portuguese.

It can often feel closer to home in English.

In Portuguese, a casa frequently refers not just to the physical house, but to one’s home/domestic space.

So arrumar a casa may be translated as:

• tidy the house
• tidy up at home
• get the house in order

The best English choice depends on the context, but in Portuguese a casa is perfectly natural here and does not sound overly literal.