De una vez

A completely new word will often catch your attention — and that's a good thing. But when a new expression is composed of words you already know, it's easy to not notice that there's anything new at all. De una vez is a good example. It's hard to figure out exactly what of one time or of once could mean.

De una vez

The key idea behind de una vez is the advantage of doing something now instead of later. Let's look at some examples:

• Firma de una vez. Sign it already, stop dawdling.
• Te aviso de una vez para que no hagas compromiso. I'm letting you know now, because if I told you later and by then you had already made a commitment elsewhere, that would be bad.
• ¿No será mejor mejor que hable con ellos de una vez? Wouldn't it be better for me to just tell them now that I'm gay, so they don't hear about it from someone else?
• ¿Nos despedimos de una vez? Shall we do our goodbyes now (in private) rather than later (in public, when it would be more awkward)?
• ¿Te doy tu recibo de una vez?. Now that you're here, would you like me to give you your receipt? That way, you won't have to come by again. It's up to you.

As you can see, in each of the examples the speaker is seeing some advantage to taking action now rather than postponing.

I associate de una vez with errands that maybe you don't particularly want to do right now, but since you're already in the neighborhood where they need to be done, you might as well do them now and save yourself a second trip. De una vez often communicates the idea of getting something over with.

Note that de una vez is not a good substitute for ahora/now in general. For example, it doesn't work well with verbs of state, so you can't say *De una vez vivo en México.

De una vez por todas

A related expression is de una vez por todas. It's more dramatic than de una vez and works well when you're talking about a recurring problem that you're finally going to deal with definitively so it won't keep happening in the future. It can sound a little telenovelera to me.

• Vamos a aclarar las cosas de una vez por todas. Let's settle this ongoing misunderstanding right now, once and for all, so that we don't keep having this problem.

If there's a difference between de una vez and de una vez por todas, it is that the latter expression works best in a situation that has been ongoing and that you anticipate being a problem repeatedly in the future if not dealt with now.