As for the election ... my instinct is to take no notice of any politician who uses the words "trillion" or "billion", because, invariably, they aren't telling the whole story.
If you earn £40,000 a year, you'd probably be happy with outgoings of £39,000 a year (ie no deficit). You'd also be happy if you had a mortgage of £120,000, even though you were carrying a substantial debt, that you weren't going to clear for at least another 20 years.