Busco mi cargador y mi llavero; siempre los guardo juntos.

Spanish often uses the simple present for actions happening right now. All are correct, with slight nuance:

• Busco mi cargador: natural, can mean “I’m looking (right now)” or “I look for (habitually).”
• Estoy buscando mi cargador: highlights the ongoing process right now.
• Ando buscando mi cargador: very common in Latin America, casual “I’m out looking for…”

No. Buscar already means “to look for,” so it takes a direct object without a preposition:

• Correct: Busco mi cargador.
• Incorrect: ❌ Busco por mi cargador. Use prepositions only in specific cases:
• Place: Busco en la mochila.
• Purpose: Busco un cargador para mi celular.
• Personal “a” (for people/pets): Busco a mi hermano.

Because the pronoun refers to two masculine nouns, cargador and llavero. For a masculine (or mixed) plural direct object, use los.

• Two feminine nouns → las
• One masculine + one feminine → still los (masculine wins in mixed groups)
• One single object (masculine) → lo; (feminine) → la

Juntos is a predicate adjective that agrees with the thing(s) kept together—in this case, the two items referred to by los (masculine plural). If both items were feminine, you’d use juntas:

• mi billetera (f) y mi tarjeta (f); siempre las guardo juntas.
• Mixed or masculine plural → juntos.

Only if you repeat the nouns. You need something (nouns or a pronoun) for juntos to refer to:

• With pronoun: Siempre los guardo juntos.
• With nouns: Siempre guardo mi cargador y mi llavero juntos.
• ❌ Siempre guardo juntos (incomplete; what is “together”?)

Yes. Common, natural options include:

• Siempre los guardo juntos.
• Los guardo siempre juntos.
• Siempre guardo mi cargador y mi llavero juntos. They’re all correct; differences are slight and mostly about rhythm/emphasis.

A semicolon is fine to link related but independent clauses. A period is also perfectly natural:

• Busco mi cargador y mi llavero. Siempre los guardo juntos. Avoid a comma between two full independent clauses (comma splice) in careful writing.

Here guardar means “to put away/keep/store.” Alternatives:

• mantener juntos: “to keep together” (more about maintaining a state than putting away).
• poner juntos: “to put together” (at a given moment), less about storage.
• meter juntos: “to put in (some container) together,” very colloquial.
• dejar juntos: “to leave together (somewhere).” For “I keep them together (as a habit/in storage),” los guardo juntos is the most idiomatic.

Because guardar takes a direct object here, so you need the direct object pronoun los. Les is indirect object:

• Direct: Siempre los guardo juntos. (“I keep them together.”)
• Indirect: Siempre les guardo sus cosas. (“I keep their things for them.”) In Latin America, using le/les as a direct object here would be considered incorrect.

Yes:

• Siempre guardo los dos juntos.
• Siempre guardo ambos juntos. (more formal) But Siempre los guardo juntos usually sounds most natural. Avoid doubling the reference (e.g., ❌ Siempre los guardo los dos).