Amy Adams and Mark Mitchell are the only National Party leadership contenders to admit having smoked marijuana and while all admit to underage drinking, Steven Joyce was the only one who had opposed lifting the drinking age to 20.
The Herald looked at the five contenders' voting records on issues from gay marriage and euthanasia to the drinking age and asked they had changed their mind on any.
We also checked whether they practiced what they preached when it came to vices.
MARIJUANA & MEDICAL MARIJUANA
All National MPs supported the first reading of a Government bill creating a legal defence for some users of medicinal marijuana, but opposed Green MP Chloe Swarbrick's wider medicinal marijuana bill.
While all were open to reform for medicinal cannabis all five were opposed to any moves towards decriminalisation or legalisation.
Their ongoing support for the government bill would depend on what changes were made in select committee, but there was some sympathy for widening the eligibility.
Adams said she was strongly opposed to anything that might lead to legalising 'loose leaf' products, but admitted to having a puff or more of the old loose leaf in her university days in the late 1980s and early 1990s. She inhaled but said she was not a regular user.
"A couple of times at parties would be about the extent of it. I was quite a giggler at parties anyway, probably."
Mitchell smoked it once as a 15-year-old with friends, but was so terrified of getting caught by the police he never did again.
Judith Collins, Steven Joyce and Simon Bridges said they had never tried it.
Both Joyce and Bridges said alcohol had been their vice of choice.
Joyce smoked cigarettes and drank alcohol when he was younger. "Adding an extra temptation didn't seem to be the right thing to do, so I never did. Never once."
For the same reason he was opposed to decriminalisation. "I'm not a fan because I think we have enough legal vices in society and adding extra ones isn't necessarily going to work."
Simon Bridges – the son of a Baptist Minister – and Mitchell were the two of the five who voted against gay marriage in 2013.
Mitchell said his vote was cast based on polling his constituents but his personal view at the time was in line with that. In hindsight he would now support it. His main concern was that marriage celebrants would not be able to refuse to conduct a gay wedding - but that had proved not to be an issue.
Bridges does not quite go so far as to say he would vote differently now, but says he is comfortable with it. "Obviously, New Zealand has moved on and so have I. It's working very well and I clearly wouldn't seek to change it."
He was from a "deeply religious" family and still had Christian beliefs himself, attending church when possible. Marriage had been seen as a religious institution.
He said while his stance on conscience issues was conservative, it was "not unthinkingly so" and he would not seek to impose his own views on others if he was leader, or any wider social reform.
Bridges, Collins and Joyce were most concerned about allowing euthanasia. Adams and Mitchell supported the first reading of Act leader David Seymour's bill while the other three opposed it.
Joyce said he was "reasonably pragmatic" on conscience issues, but he was uncertain about euthanasia.
"I struggle with it. I do understand the concerns of those that are in favour of it but I am really worried about where it leads.
I just think we've got to be careful not to risk another harm."
Bridges said there were sanctity of life issues and he was also worried that in overseas countries which allowed it, the numbers had grown. "It's a thin end of the wedge issue."
Mitchell said he would canvas his electorate, but would oppose it at further stages unless safeguards were tightened. Adams too wanted tight restrictions and safeguards.
Collins was concerned about the mixed messages it would send and the impact on youth suicide and mental health. "I would need to be convinced and I don't think that's possible."
All five admitted having their first drink at 18 or younger - at a time the drinking age was 20. Only Joyce supported a drinking age of 18.
Amy Adams and Judith Collins voted to lift the the drinking age to 20 in 2012 – but both were advocates of failed attempts to introduce a 'split-age' which would allow 18-year-olds to drink at on-licenses but not buy alcohol from off-licenses. Their views on the the split age remain the same.
Joyce had supported keeping it at 18 years old because he considered that was reasonable. Bridges and Mitchell had both believed 20 was appropriate but Mitchell said he was now "more relaxed" about 18 because drinking behaviour had changed.
Mitchell said his own background as a police officer did influence some of his decisions on matters of drugs and alcohol.
Bridges said he had his own first drink "well before then." "But two wrongs don't make a right."
PM Jacinda Ardern has promised to review the 40-year-old abortion law. All five were against moves to further liberalise or tighten the law - and concerned it would be a divisive debate.
Amy Adams said some of the language in the current law was out dated but was not in favour of "large scale" liberalisation or tightening.
Collins said there were 13,000 - 14,000 abortions a year so the law was already quite liberal.
"I don't see why this is an issue for the Prime Minister. I think she should get on and do her job, focus on the economy and law and order and leave issues like this. Parliament has repeatedly chosen over the years not to go back to this because it is divisive."
Bridges was also concerned about the divisiveness and any review that might liberalise the law. "It should be "rare, safe and legal and I think the emphasis there is on rare. I think that's where the vast majority of New Zealanders are." Mitchell and Joyce did not believe it should change.