Learn Hardcore Indonesian: Kecuali presentasi penting, sebaiknya kita pulang setelah magrib. - Except for an important presentation, we should go home after sunset.

With a noun phrase, kecuali = except (for): example, Semua hadir kecuali Budi.
With a clause (often introduced by ada/kalau/jika), kecuali = unless: example, Kecuali ada presentasi penting, sebaiknya kita pulang setelah magrib. In your sentence, Kecuali presentasi penting is a short, spoken-style way to mean “unless (there’s) an important presentation.” Adding ada makes it clearer and more natural.

Is the original sentence natural as is, or should I add ada/kalau after kecuali?

It’s understandable, but most speakers would find it smoother with ada (or kalau ada):

Kecuali ada presentasi penting, sebaiknya kita pulang setelah magrib.
Or place the exception after the main clause: Sebaiknya kita pulang setelah magrib, kecuali (kalau) ada presentasi penting. Using Kalau tidak ada… is also very common: Kalau tidak ada presentasi penting, sebaiknya kita pulang setelah magrib.

Why is there a comma after the kecuali phrase? Is it required?

Initial exception/condition phrases are typically set off with a comma in Indonesian: Kecuali ada presentasi penting, … It’s standard and recommended. If you move the exception to the end, you also use a comma: …, kecuali kalau ada presentasi penting.

Is sebaiknya the same as should? Are there alternatives?

sebaiknya is an advisory modal meaning “it would be best / should,” polite and non-imperative. Alternatives:

lebih baik: “better / it’s better to…” (neutral suggestion) — Lebih baik kita pulang…
seharusnya: “ought to / should (normatively)” — stronger tone. All are fine; sebaiknya is a gentle recommendation.

Can I move sebaiknya in the sentence?

Yes:

Sebaiknya kita pulang setelah magrib.
Kita sebaiknya pulang setelah magrib. Both are natural; the nuance difference is minimal.

Why use kita and not kami?

kita = we including the person you’re speaking to.
kami = we excluding the person you’re speaking to.
Here kita invites the addressee into the plan (“we, you and I, should go home…”).

What exactly does magrib refer to?

magrib is the time around sunset; it also names the Muslim Maghrib prayer (just after sunset). In everyday Indonesian, setelah magrib means “after sundown/after the Maghrib prayer time,” i.e., after dark in the early evening.

How should I spell and capitalize magrib?

Standard Indonesian uses magrib (no h) and it’s not capitalized unless at the start of a sentence or in a title. You’ll also see maghrib in religious contexts; both are understood, but general writing prefers magrib.

Can I use sesudah instead of setelah? Any other options?

Yes. setelah and sesudah are interchangeable. Other options:

usai / seusai (slightly formal): Kita pulang seusai magrib.
habis / abis (colloquial): Kita pulang habis magrib.
ba’da (Arabic-derived, often in announcements): ba’da magrib.

Do I need an article before presentasi penting? Should I add sebuah?

Indonesian has no articles. presentasi penting already covers “an important presentation/important presentations.” Add sebuah only if you want to stress singularity: Kecuali ada sebuah presentasi penting, … (optional and a bit heavier).

What’s the difference between presentasi penting and presentasi yang penting?

presentasi penting: an important presentation (describes a quality; often indefinite/generic).
presentasi yang penting: the presentation that is important (identifies a specific one among others). Use yang when you’re specifying a particular, known item.

Does pulang need ke rumah? Is pulang ke rumah redundant?

pulang already means “go (back) home.” pulang ke rumah is usually redundant, though people may say it for emphasis. For returning to a non-home place, use kembali or colloquial balik with a destination: kembali ke kantor, balik ke kampus.

Difference between pulang, balik, and kembali?

pulang: go home/return to one’s base; neutral.
balik: go back/return; colloquial and flexible (e.g., balik dulu).
kembali: return (more formal/literal); also means “again.” With a destination: kembali ke…

How do I say “before Magrib” instead?

Use sebelum magrib:

Kita sebaiknya pulang sebelum magrib.
With an exception: Kita sebaiknya pulang sebelum magrib, kecuali kalau ada presentasi penting.

Do I need to negate the main clause when using kecuali?

No. Indonesian allows a positive main clause modified by an exception: Sebaiknya kita pulang setelah magrib, kecuali (kalau) ada presentasi penting.
If you want a more explicitly conditional structure, use kalau tidak…: Kalau tidak ada presentasi penting, sebaiknya kita pulang setelah magrib.

Can I use selain instead of kecuali?

Be careful. selain usually means “other than/besides” (often additive), not a blocking exception:

Selain presentasi penting, kita pulang setelah magrib is awkward/ambiguous. Use kecuali for true exceptions that suspend the main statement:
Kita pulang setelah magrib, kecuali kalau ada presentasi penting.