Learn Hardcore Spanish (Spain): De vez en cuando quito el azúcar del café para dormir mejor. - From time to time I remove the sugar from my coffee to sleep better.

de vez en cuando = “every now and then,” usually feels a bit less frequent/more occasional.
a veces = “sometimes,” neutral frequency. Both are fine in Spain; choose based on the nuance you want.

Where can de vez en cuando go in the sentence? Do I need a comma?

Placement is flexible:

Beginning: De vez en cuando, quito... (comma is common but optional)
Middle: Quito, de vez en cuando, el azúcar... (two commas for parenthetical style)
End: Quito el azúcar del café de vez en cuando. All are correct; initial position with a comma is very natural.

Why is quito in the simple present? Could I say suelo quitar?

Spanish simple present expresses habitual actions, so quito is perfect. Soler + infinitive (e.g., suelo quitar) means “I tend to/usually do,” which suggests a regular habit. With de vez en cuando (occasional), suelo can sound contradictory or redundant; prefer either:

De vez en cuando quito... or
Suelo tomar el café sin azúcar. (without the “de vez en cuando”)

Does quitar mean “to quit”? What’s the difference between quitar, dejar, sacar, and retirar?

quitar = to remove/take away something from somewhere/someone: Quito el azúcar del café.
dejar = to quit/stop doing/using: Dejé el azúcar. (I cut out sugar)
sacar = to take out (from inside to outside): Saqué el azúcar del armario.
retirar = to remove (often more formal or deliberate): Retiró el azúcar de la mesa. So don’t confuse quitar with “to quit”; for that, use dejar.

Is quito el azúcar del café the most natural way to say this in Spain?

It’s understandable but can sound like you added sugar and then literally remove it from the cup. In Spain, to mean “I skip sugar in my coffee,” more idiomatic options are:

Tomo el café sin azúcar.
No le echo azúcar al café.
No le pongo azúcar al café.

Should it be del café or al café? What’s the difference between quitar algo de and quitar(le) algo a?

quitar algo de [lugar]: removing something from inside/onto a place or container: quitar el azúcar del café (from inside the coffee).
quitar(le) algo a [alguien/cosa]: removing something that belongs to or is attached to someone/something: quitarle el azúcar al café (take sugar away from the coffee as its attribute). In practice, for this idea Spanish speakers often avoid both and just say: No le echo azúcar al café.

Can I use sacar instead of quitar here?

Not normally. Sacar el azúcar del café suggests physically extracting sugar granules from the cup (odd once it’s dissolved). Use quitar for removal in general, or better: tomar el café sin azúcar / no echar azúcar.

Why el azúcar? Is azúcar masculine or feminine? What about adjectives?

azúcar has ambiguous gender (masculine and feminine are both accepted), but in the singular it’s most commonly used as masculine in Spain: el azúcar. Adjectives typically agree in masculine: el azúcar blanco / moreno. Feminine agreement also occurs regionally: el azúcar blanca / morena, but masculine is more standard.

Could I drop the article and say quito azúcar del café?

Grammatically possible, but it implies removing “some sugar,” which is odd once sugar is dissolved. Quito el azúcar del café suggests removing the (known) sugar altogether. For the intended idea (not using sugar), idiomatic Spanish avoids both and says: Tomo el café sin azúcar or No le echo azúcar al café.

Why del and not de el?

Because de + el contracts to del: del café. The contraction does not happen with the pronoun él (e.g., de él = “of him”).

Why para dormir mejor and not por dormir mejor?

para + infinitive expresses purpose/goal: you skip sugar in order to sleep better. por gives cause/reason and sounds wrong here. Compare:

Lo hago para dormir mejor. (goal)
Me castigaron por dormir en clase. (cause)

Why is it dormir and not duermo after para?

In Spanish, verbs after any preposition (e.g., para, por, sin, de, a, en, con) must be in the infinitive: para dormir, not para duermo.

Is para poder dormir mejor better than para dormir mejor?

Both are correct. para poder dormir mejor adds a nuance of “to be able to,” emphasizing enabling the action. In everyday speech both forms are common; choose based on the nuance you want.

Is mejor an adverb here? Could I say mejores or más mejor?

Yes, mejor works as an adverb (comparative of bien) and is invariable: dormir mejor. You don’t say mejores here, and más mejor is nonstandard. If you don’t want a comparison, use dormir bien.

What would the sentence look like with more idiomatic Spain phrasing?

Natural options include:

De vez en cuando, tomo el café sin azúcar para dormir mejor.
De vez en cuando, no le echo azúcar al café para dormir mejor.
A veces tomo el café sin azúcar para dormir mejor.

Any other small stylistic tweaks I should know?

A comma after an initial De vez en cuando is common: De vez en cuando, ...
If you mean night-time specifically, add por la noche: ... para dormir mejor por la noche.
In Spain, echar and poner are the everyday verbs for adding sugar: no le echo/pongo azúcar sounds very natural.