when does a sentence become a run on
Sentence clause structure A run-on or fused sentence consists of two or more independent clauses (i.e., clauses with subject and predicate) that are joined without any appropriate punctuation. An example of such a grammatically incorrect sentence could be, "It is nearly half past five we cannot reach town before dark." Some common remedies would be to separate the two independent clauses (between "five" and "we") with either a period [...five. We...], a comma and conjunction (...five, and we...), or a semicolon (...five; we...). Joining the two independent clauses with only a comma is actually another common grammatical error, the comma splice. James Joyce's novel Ulysses employs streams of consciousness, which takes literary license by intentionally breaking this grammatical rule by use of long, punctuation-free, run-on sentences, particularly in the final chapter "Penelope".
Running on Empty (song) The song may be meant to describe the rigors of a musician's day-to-day life on the road, and its effect on his life as a whole, in connection with the themes of much of the album, but the lyric is more generally applicable, as well: