Reduza o gasto supérfluo; acompanhe o orçamento pessoal.

Reduza is the imperative form of reduzir used with você. In Brazilian Portuguese, the você command usually looks like the present subjunctive form.

• reduzir = to reduce
• (você) reduza = reduce

So this sentence is giving advice or an instruction: Reduce...

Because the sentence is using the você form, not tu.

For commands:

• tu: reduz
• você: reduza

In Brazil, você is very common, so learners will often see commands like:

• faça
• acompanhe
• reduza

rather than the tu forms.

Gasto here is a noun, not a verb. It means spending, expense, or expenditure.

• gasto = spending / expense
• supérfluo = unnecessary / superfluous / non-essential

So o gasto supérfluo means something like:

• unnecessary spending
• non-essential expense
• superfluous spending

In practical financial language, it refers to money spent on things you do not really need.

Because it agrees with gasto, which is singular.

• o gasto supérfluo = the unnecessary spending
• os gastos supérfluos = unnecessary expenses / unnecessary expenditures

Portuguese adjectives normally agree in gender and number with the noun:

• gasto supérfluo → masculine singular
• despesa supérflua → feminine singular
• gastos supérfluos → masculine plural
• despesas supérfluas → feminine plural

Yes, absolutely. In fact, Reduza os gastos supérfluos may sound even more natural in many everyday contexts.

Compare:

• Reduza o gasto supérfluo = reduce unnecessary spending
• Reduza os gastos supérfluos = reduce unnecessary expenses

The singular version sounds a bit more general or abstract, while the plural version points more directly to individual expenses.

Acompanhe is the você command form of acompanhar.

Although acompanhar often means to accompany, in this context it means:

• to follow
• to keep track of
• to monitor

So acompanhe o orçamento pessoal means:

• keep track of your personal budget
• monitor your personal budget

This is a very common extended meaning of acompanhar in Portuguese.

The semicolon links two closely related commands:

• Reduza o gasto supérfluo
• acompanhe o orçamento pessoal

It shows a stronger break than a comma, but it keeps the two ideas connected. In English, this is similar to writing:

• Reduce unnecessary spending; monitor your personal budget.

It gives the sentence a slightly formal, written, advisory tone.

Orçamento pessoal means personal budget.

• orçamento = budget
• pessoal = personal

In Portuguese, adjectives often come after the noun, unlike English:

• orçamento pessoal = personal budget
• gasto supérfluo = unnecessary spending

That is one of the most common word-order differences English speakers notice.

Portuguese uses definite articles more often than English does.

So:

• o gasto supérfluo
• o orçamento pessoal

can refer to the idea in a general sense, not only one specific item already mentioned.

English often drops the article in similar advice:

• Reduce unnecessary spending
• Monitor your personal budget

But Portuguese commonly keeps it.

Yes, it sounds neutral to somewhat formal.

Reasons:

• it uses the você command forms: reduza, acompanhe
• it uses fairly formal vocabulary such as supérfluo
• the semicolon gives it a polished written style

This sounds like advice you might see in:

• a financial article
• a self-help guide
• a budgeting app
• an educational text

In everyday speech, someone might choose simpler wording, such as:

• Corte gastos desnecessários e acompanhe seu orçamento.

They are related, but not always identical.

• gasto often means spending or money spent
• despesa often means expense or a more specific financial outlay

In many contexts, they overlap a lot. For example:

• reduzir gastos = reduce spending / cut expenses
• reduzir despesas = reduce expenses

Very roughly:

• gasto can sound a bit broader and more general
• despesa can sound a bit more technical or accounting-like

Both are common in personal finance language.

Supérfluo is correct and fairly common in formal or educated language, but it is a bit more elevated than everyday speech.

Simpler alternatives include:

• desnecessário = unnecessary
• não essencial = non-essential

So you could also say:

• Reduza os gastos desnecessários.
• Reduza os gastos não essenciais.

These may sound more natural in casual modern Brazilian Portuguese.

With tu, the commands would normally be:

• Reduz o gasto supérfluo; acompanha o orçamento pessoal.

However, this depends on regional usage, because tu forms vary a lot across Brazil. In many places, people use tu but still mix in verb forms associated with você in casual speech.

For a learner, the original você version is a safe and widely understood choice:

• Reduza o gasto supérfluo; acompanhe o orçamento pessoal.