Isn't "a" or "the" necessary in front of "time"?
Native speaker’s answer
Rebecca
In casual conversation, it is common to omit words when speaking for purposes of brevity, or to make a sentence less formal. In this case, the full sentence with no omissions is "it's time to switch the lights out." The speaker has omitted the "it's" here, but it does not change the meaning of the sentence. You can think of this as an example of the "short form" of speaking, similar to when people write in short form. Ex: Food okay? (Is the food okay?) Ex: So hot outside today. (It's so hot outside today.)