Personally, I avoid deus ex machina like the plague - if you have to use one, it means you failed to set up the universe and the plot properly. It's like a whodunnit where there's no actual way for the reader to identify the perpetrator before the climactic reveal: there's no sense of closure for the reader.
Charles StrossFatal accidents never happen because of just one mistake. It takes a whole chain of stupids lining up just so to put a full stop at the end of an epitaph.
Charles StrossI reckon I can count on 30 more writing years, averaging a book a year (I can't keep up the 2-2.5 a year I used to do these days). And these days I've gotten round to wondering, for each new idea, "do I want to be remembered for this?" before I get to the point of spending a year on it.
Charles StrossIf I write too much of anything for too long, I burn out on it. So it helps to vary my output from year to year.
Charles Stross