"Section 77 is a blunt tool, it's essentially like a flow chart," Moore says.
"If you have a spouse or a de facto partner then they get the first $155,000 and a third of the balance (what's left over). The other two thirds goes to the kids.
If you've got kids and don't have a partner, then it goes between the kids, Moore adds.
"If you don't have any kids, it goes to your parents.
"Under $15,000? Easy as. I get people calling me up quite often in that situation and it's just a case of steering them in the right direction."
Things get complicated the second someone has more than $15,000 and no will.
The first step is to apply for Letters of Administration (to be an appointed administrator of the will), which costs between $4000 and $5000, Moore says.
"Let's say you've got $50,000 in your Kiwisaver, a couple of kids, and a partner who may not be the parent of your kids.
Naturally, you'd assume that it would go to your kids in this instance, Moore says.
But, it doesn't, with the first $155,000 going straight to the partner.
"I deal with this quite a lot, where someone will call me up and they're very, very upset.
"They'll say 'my kids aren't getting anything, and their dad died. His new partner has taken everything'."
While that might sound unfair, there's very little he can do, Moore says.
"It's the law, and unfortunately, the law is not always fair."
Alex McKenzie, 34, says writing a will has never crossed his mind.
While he doesn't have "heaps of stuff", his total assets are just north of $15,000, with a Kiwisaver account thrown in as well.
"To be honest, the only thing I've thought about when I die is the playlist I want at my funeral," McKenzie says. "I don't want them assuming I liked Guns n' Roses or something."
Writing a will just wasn't a priority for McKenzie just yet.
"In saying that, it's probably the case for a lot of people around about my age."
The ease of constructing a will depends completely on someone's personal situation, Moore says.
"Having five children to three different people, that's going to be a lot more complicated than if you've got two children to the same person.
"If you do have a partner, it's a good idea to make wills at the same time. They can reflect each other, and everyone's on the same page as to what's happening."
While it's possible to write one of your own, Moore says he wouldn't recommend it.
"I've had clients regularly come in with what seems like a nice simple will, and once we test it out, it's actually an incredibly complicated will."
A typical example Moore comes across is the assumption joint home owners each get half of it, which in reality, they don't.
"You can write a will and say 'I give everything to my children and nothing to my partner', but if the house is owned jointly, it will pass straight to the other owner and won't form part of the estate," Moore says.
The same rule applies for a joint bank account.
"My main message would be, spending a bit of money to get a will is going to potentially save a lot of heartache and a lot of cost to your family in the future."
Public Trust is the country's largest provider of wills and estate administration, and less than 3 per cent of its portfolio is made up of people aged 40 years and under.
That's according to its general manager of retail, Vanessa Dudley, who says there's a lot of work to do in order to get that percentage up.
"Three per cent is such a small number, especially when you think about that $15,000 figure," Dudley said.
"Most people have got a car and some form of Kiwisaver, so that's not a hard amount to get to."
Dudley says people don't realise that without a will, someone's belongings can be distributed among people who may not be particularly close to them.
If you haven't left any clear instructions behind, it's up to the administrator of the estate to sort things out.
"If we're talking about that 20- to 30-year-old space, you may have parents, siblings, grandparents, aunts and uncles," Dudley said.
All of those people can receive a portion of your estate, Dudley says, which may not be what's wanted.
"You may want the watch you got given on your 21st birthday to go to your baby brother, but that would never happen."
Reviewing and renewing a will is also important, Dudley says.
"Life changes and moves on, and it's important to keep it up to date.
"You've got to have one in the first place though, don't you?"
Bonnie Wilson, 43, says she got a will at the age of 21.
"The lawyer who did our house purchase did mine and my husband's for free," Wilson said.
They haven't updated them since.
"I've just never got around to it, partly because of the cost, and partly because it hasn't really been a priority."
Wilson said her main concern when she wrote it was the fate of her children if both she and her husband passed away at the same time.
"You don't really want to think about it, but it was more if both of us went in a flaming car wreck or something.
"My dad and my stepmother were named (as guardians) back then, but that relationship has now ended."
At the time of the will, Wilson and her husband only had one child. They now have three.
"Would my ex-stepmother still get a say? I don't know. I guess she'd only get the first one, who's 24 now anyway.
"My youngest is 15, so I think my oldest child would probably take her in."
Wilson says she trusts her kids to be "fair" when it comes to dividing up their parents' assets.
"I go to auctions sometimes and see all the stuff that families have sold off. I'd be mortified if they did that with my souvenir teaspoons and teacups."
Unlike McKenzie, she said she wouldn't mind if Guns n' Roses was played at her funeral.
"I could think of worse. If they played Nickleback, I'd be mad.
"Maybe I'll add that into my will when I finally get round to updating it."
Public Trust provides online will templates, and Dudley says if you have simple personal circumstances, completing one can only take 20-30 minutes.
"Whatever stage you're at, take half an hour, grab a cup of coffee, log on and have a look. It's worth doing."
It's hard to know the value of your belongings until they are all written down, though.
"When people are under 35, there is this perception that it's not really relevant, and 'I don't have enough assets, anyway'," Dudley says.
"It's not about having oodles of money or lots of houses, or even a house these days.
"It's not all about the dollars, either. Another thing we (Public Trust) talk about quite a bit is the legacy element."
Those are things such as crafts, heirlooms, stories, or even recipes - things that are only valuable to someone who is close to you.
"It may even be Grandpa's stamp collection. It might not be worth any money, but it's still Grandpa's stamp collection," Dudley says.
"When someone comes in and cleans out your house because you've passed away, to them it's just whole bunch of stamps in a box."