По будням я люблю завтракать дома, а не в кафе.

Yes. По будням is a very common, natural way to say on weekdays or during the workweek.

Literally, it uses по plus the plural of будни (weekdays / workdays). In this kind of time expression, it gives the idea of something that happens regularly on those days.

So По будням я люблю... means something like:

• On weekdays, I like...
• During the week, I like...

It sounds habitual, not like one specific day.

Because after по in this time expression, Russian uses the dative plural.

• dictionary form: будни
• dative plural: будням

So:

• по будням = on weekdays
• compare: по утрам = in the mornings
• по вечерам = in the evenings

This pattern is very common for repeated time expressions.

Because in Russian, after любить when you mean to like doing something, you normally use an infinitive.

So:

• люблю завтракать = I like to have breakfast
• люблю читать = I like to read
• люблю гулять = I like to go for walks

This is similar to English I like to eat / I like eating.

Because завтракать is imperfective, and that is usually what Russian uses after любить for a general habit or repeated activity.

• завтракать = to have breakfast, as a repeated/general activity
• позавтракать = to have breakfast once, to finish having breakfast

In this sentence, the speaker is talking about a habitual preference, so завтракать is the natural choice.

If you said люблю позавтракать, it could sound more like I like to have a nice breakfast once in a while / I enjoy sitting down and having breakfast, but it is less neutral here.

Because дома is an adverb meaning at home.

• дома = at home
• в доме = in the house / inside the building

So in this sentence:

• завтракать дома = to have breakfast at home

If you said в доме, it would focus more on the physical building, not the everyday idea of home.

Also, в дома is incorrect here.

Because а is often used in Russian to show contrast between two alternatives.

Here the meaning is:

• at home, not in a café
• rather at home than in a café

So а не is very natural.

Compare:

• дома, а не в кафе = at home, not in a café
• чай, а не кофе = tea, not coffee

Но usually means but in a different sense, often introducing a new idea rather than directly contrasting two options.

Because кафе is an indeclinable noun in Russian. That means its form stays the same in all cases.

So:

• кафе
• в кафе
• из кафе
• около кафе

The form does not change.

In this sentence, after в meaning location (in / at a café), Russian normally uses the prepositional case, but with кафе, the form happens to stay кафе.

Because а is a coordinating conjunction, and in Russian it is normally separated by a comma when it connects contrasting parts.

So:

• ..., а не ...

This comma is standard.

Even though the second part is short, the contrast is strong, so the comma is still needed.

Yes, Russian word order is flexible.

The original sentence:

• По будням я люблю завтракать дома, а не в кафе.

puts по будням first, which sets the time frame right away: on weekdays.

Other possible word orders include:

• Я люблю по будням завтракать дома, а не в кафе.
• Я по будням люблю завтракать дома, а не в кафе.

These are all understandable, but the original sounds very natural because it starts with the time expression.

Yes, Russian could leave it out:

• По будням люблю завтракать дома, а не в кафе.

This is still grammatical, because люблю already shows I.

However, я is often included for clarity, rhythm, or emphasis. In a neutral sentence like this, both versions are possible, but the version with я sounds slightly fuller and more explicit.

Not necessarily every single one in a strict mathematical sense. It usually means as a general habit.

So the sentence suggests:

• This is what I normally prefer on weekdays

It describes a routine or preference, not an absolute rule with no exceptions.

Yes. In English, the most natural translation is often at a café.

Russian в кафе literally uses in, but with places like cafés, restaurants, shops, and offices, English often prefers at in natural translation.

So:

• в кафе = in a café / at a café

Both are possible in English, depending on context and style.