I often struggle to decide what sounds right when I need to use direct object pronouns. Lessons on these pronouns have not been much help because they teach that when using a direct object pronoun it is okay to either leave it on its own or attach it to the infinitive, and "neither method is 'better' than the other".
Lo quiero ver.
In simple examples like this, I can see how both ways sound ok.
However, in longer statements, especially negative ones, I often find myself stumbling if I try to say the version with the pronoun out front. For example, I find the second version much easier to say in this example:
Juan no lo necesita lavar.
Juan no necesita lavarlo.
(If there are indirect object pronouns too, I think I often prefer the second version where everything is attached to the infinitive:)
No te lo quiero decir.
No quiero decírtelo.
I'm not a native speaker, so I might just find one way hard to say and don't have enough exposure to tell what sounds right.
I'd like to know: In what ways are the styles not exactly the same? For example, is one way more common in speech or in writing? Does it vary for the short or the complicated examples? Is there a reason you choose one way or the other (sounds more formal or friendly, makes the point better)?