I've been a deputy workplace union leader and been called Deputy Dawg on my rounds, so I understand a bit of what deputies go through.
Only two Deputy Prime Ministers have gone on to become Prime Minister: Paul Keating and Julia Gillard.
The title was created to honour its first bearer, Sir John McEwen on 10th of January 1968. Prior to that, there had been unofficial deputy leaders but it took placating a former acting prime minister to formalise things.
Succeeding 'Black Jack' in the deputy's chair was Doug Anthony. This was so not only in that he immediately followed his term, but by virtue of his leadership of the Country Party cum National Country Party cum whatever sounded authentically rural at the time, automatically making him Deputy Prime Minister every time a conservative party was returned to power (the same pulling power, incidentally, that had made McEwen caretaker Prime Minister). The ruler of the rump party, whose own vote is low but still gives them authority by dint of their constituency. Enough to give them cabinet posts and the deputy leadership. So Anthony served under Gorton, McMahon, and Fraser.
Lance Barnard#, Jim Cairns#, and Frank Crean played musical chairs in the deputy spot in those three years before the Whitlam government was dismissed.
Another seven and a half years of Doug Anthony later and the antipodes were ready for the shattering consequential nature of Lionel Bowen. He all but reigned for some seven years before an upstart named Paul Keating took over and lasted a year and two months (I bet he's sad about that) in the job
His successor was Brian (don'tr ask me) Howe# who was followed by.Kim (Bomber) Beazley, a man who made several runs at the Prime Ministership as leader of the Opposition.
When Howard heads to Hawks Head, he needs Tim Fischer, John Anderson or Mark Vaile to cover for him.
Rudd could doubtless have fared better with a different deputy, one who didn't dislodge him shy of a full term, after he returned the Party to victory. But then Julia Gillard doesn't have much to fear from Wayne Swan.
[I don't normally feel it necessary to distance myself from posts and sites I link to but those right wing ones lambasting Barnard and Cains do not represent my perspective whatsoever. The scholarly analysis of Crean, placing him in the fiscal context of others who'd had to manage the economy, doesn't need an asterisk (or hash) because it is well argued]