Learn Hardcore Polish: Stary odkurzacz stoi w garażu, ale nowego używamy codziennie. - The old vacuum cleaner stands in the garage, but we use the new one every day.

The basic (dictionary) form is garaż (nominative).
After w meaning “in” (location, not movement), Polish normally uses the locative case.
The locative singular of garaż is garażu.

So:

Samochód jest w garażu. – The car is in the garage. (locative)
Wchodzę do garażu. – I go into the garage. (here do also triggers genitive: garażu)

You would only use a different case with w if you were talking about movement into something (then it takes the accusative), e.g.:

Wchodzę w garaż – I walk into the garage (much less common than do garażu, but shows the pattern).

In your sentence, nothing is moving; it’s just located there, so w garażu (locative) is correct.

Why do we say just nowego in the second part and not repeat odkurzacza?

Polish, like English, can omit a repeated noun if it is obvious from context, and leave only the adjective, which then means “the new one”.

The full sentence could be:

Stary odkurzacz stoi w garażu, ale nowego odkurzacza używamy codziennie.

Because odkurzacz has already appeared, it’s natural to shorten it to:

…ale nowego używamy codziennie. – “…but we use the new one every day.”

So nowego here means “the new (vacuum cleaner)”.

Why is it nowego, not nowy?

Because nowego has to match the case that the verb używać requires.

odkurzacz is masculine inanimate.
After używać (“to use”), standard Polish uses the genitive case for the object.

Full form:

Używamy nowego odkurzacza. – We use the new vacuum cleaner.
- nowego = genitive masculine singular (agreeing with odkurzacza in genitive).

When you drop the noun odkurzacza, the adjective keeps the same case:

Używamy nowego. – We use the new one.
(still genitive masculine singular)

Nowy is nominative (or sometimes accusative). In this sentence you cannot say:

✗ używamy nowy – incorrect in standard Polish grammar.

Why does używamy take the genitive case? Could I say używamy nowy odkurzacz?

In standard Polish, the verb używać (“to use”) takes an object in the genitive:

używać czego? – “to use what?” (genitive)

So:

używam telefonu → formally it should be używam telefonu (gen.), but here form is same as acc.
używam nowego odkurzacza – I use the new vacuum cleaner. (genitive: nowego odkurzacza)

Therefore:

(My) używamy nowego odkurzacza. – correct (standard)
(My) używamy nowy odkurzacz. – often heard in everyday speech, but considered incorrect in careful/standard language.

In your sentence, because of that genitive requirement, we get nowego (odkurzacza), not nowy (odkurzacz).

Why is there no word for “we” in nowego używamy codziennie?

Polish is a “pro-drop” language: personal subject pronouns (ja, ty, my, wy) are usually omitted because the verb ending already shows the person and number.

używam – I use
używasz – you (sg.) use
używamy – we use
używacie – you (pl.) use

So:

(My) używamy nowego codziennie. – my is optional.
English needs “we use”; Polish normally just says używamy.

You would add my only for emphasis/contrast, e.g.:

My używamy nowego, a oni używają starego. – We use the new one, but they use the old one.

Why does the sentence use stoi (“stands”) instead of jest (“is”)?

Both are possible, but they have slightly different nuances.

Stary odkurzacz stoi w garażu…
- Literally: “The old vacuum cleaner is standing in the garage…”
- Emphasises its upright/standing position and gives a more visual feeling (“it just stands there”).
Stary odkurzacz jest w garażu…
- Neutral: “The old vacuum cleaner is in the garage…”
- Focus is only on location, not on position.

For many upright objects (fridges, wardrobes, vacuum cleaners), Poles very often say stoi in everyday speech. Using stoi here is perfectly natural and maybe slightly more vivid than jest.

Why is the verb używamy (imperfective) used with codziennie? Could we use a perfective verb instead?

Codziennie (“every day”) describes a repeated, habitual action. In Polish, such actions are normally expressed with imperfective verbs.

używać – imperfective (“to use” in general / habitually)
użyć – perfective (“to use (once), to make use of (in a single event)”)

So:

Używamy nowego codziennie. – We use the new one every day. (habit → imperfective)
Użyjemy nowego odkurzacza jutro. – We will use the new vacuum cleaner tomorrow. (one planned event → perfective)

With codziennie, the perfective would sound wrong or at least very odd; it clashes with the idea of regular repetition.

Can we change the word order? For example: W garażu stoi stary odkurzacz or Używamy codziennie nowego?

Yes. Polish word order is relatively flexible, and you can move elements around to change emphasis, as long as the grammar relations remain clear.

All of these are grammatical:

Stary odkurzacz stoi w garażu, ale nowego używamy codziennie. (neutral)
W garażu stoi stary odkurzacz, ale nowego używamy codziennie.
– Emphasises the location first: In the garage there stands an old vacuum cleaner…
Stary odkurzacz stoi w garażu, ale używamy nowego codziennie.
– Slightly more neutral/object-focused order in the second clause.
Stary odkurzacz stoi w garażu, ale codziennie używamy nowego.
– Emphasises codziennie (“every day we use the new one”).

Things you cannot do: you can’t normally separate a preposition from its noun (✗ w stary odkurzacz garażu stoi), and you must keep verb forms matching their subjects.

So word order is flexible mainly for focus/emphasis, not for basic grammatical function.

What gender is odkurzacz, and how does that affect stary / nowego?

Odkurzacz is masculine inanimate.

That determines how adjectives and pronouns agree with it:

Nominative singular (subject):
- stary odkurzacz – the old vacuum cleaner
- ten odkurzacz – this vacuum cleaner
Genitive singular (after używać):
- nowego odkurzacza – of the new vacuum cleaner
- tego odkurzacza – of this vacuum cleaner

In your sentence:

stary odkurzacz – nominative masculine singular (subject of stoi)
nowego (odkurzacza) – genitive masculine singular (object of używamy)

If the noun were feminine, the forms would change, e.g.:

stara pralka stoi w garażu, ale nowej używamy codziennie.
(pralka “washing machine” is feminine → stara / nowej)

Where are the English articles “the / a” in this Polish sentence?

Polish has no articles. There is no direct equivalent of “a, an, the”.

So stary odkurzacz can mean, depending on context:

the old vacuum cleaner
an old vacuum cleaner

Context and sometimes word order or additional words (like ten = “this”) show whether we are talking about something specific or non-specific, but there is no separate article word.

In your sentence, given the contrast with nowego, the natural English translation would be “the old vacuum cleaner” and “the new one”, but in Polish that specificity is simply understood from context.

Why is there a comma before ale?

In Polish, you normally put a comma before the conjunction ale when it joins two clauses (two separate predications):

Stary odkurzacz stoi w garażu, ale nowego używamy codziennie.

Each part has its own verb (stoi, używamy), so they are two clauses joined by ale, and a comma is required.

This is very similar to English punctuation:

“The old vacuum cleaner stands in the garage, but we use the new one every day.”

(For comparison, in Polish you do not always put a comma before i (“and”) in the same way, so the rule for ale is stricter.)

Could we say każdego dnia instead of codziennie? Is there a difference?

Yes, you can.

Używamy nowego codziennie.
Używamy nowego każdego dnia.

Both mean “We use the new one every day.”

Differences:

codziennie – adverb, short and very common.
każdego dnia – literally “of every day” (genitive), can sound a bit more emphatic (“every single day”) or slightly more formal/literary depending on context.

In everyday speech, codziennie is more frequent, but każdego dnia is perfectly normal.