Up there with the most awful thoughts that you can have as a parent is not being there to raise your own children. No wonder so many parents don't get round to appointing a legal guardian for their kids.
There's another reason parents put off the decision about who would look after their children if they died: It's almost impossible to find someone who ticks all the boxes.
After all, how can you find anybody who could not only help your kids manage the most awful grief imaginable, but also ensure that their childhood stays as happy as you'd want it to be?
The problem is that if you don't choose, someone else might do it for you – whether it's social services or the courts.
Sure, you might assume your mum, your sister or your best friend will do it, but without them having agreed to it and without you having recorded it in your will, it may not actually happen.
"We had a case where all the family members and friends that the parent had assumed would take on the child said they didn't feel they could and consequently the child was adopted," says Liz Koole, family services team leader at the charity for bereaved children Winston's Wish.
"Nobody ever wants to think about themselves dying, least of all if you're a parent of children who are still growing up, but it can and does happen, and it can be really hard for a child if there is no plan," she says.
Her advice is to start by imagining yourself in your child's shoes. "Where would they want to be? It might be family or it might be friends, but the most important thing is that your child will feel they're wanted and with someone who will love them for themselves, not out of duty or money."
Are the guardians you're considering loving, she adds? Are they good role models? How affectionate are they? And if they're young, how mature are they? These are all things that will affect your child's everyday life if you weren't there.
Usually, parents choose another family with children. The assumption is that they'll already have a child-centred approach to life.
But if they have children of their own, will yours become second fiddles? Or is the couple sufficiently loving and giving that they will make your child feel loved no matter what? This is something to think about too, says Koole.
"It might feel reassuring that your best friend will gladly take on your children, for instance, but the introduction of a new child into her family, no matter how lovely they are, might cause tensions and complications that make your child's life really hard - and it's essential to think about that," she explains.
A child who has been used to being an only child might find it really hard to share, she adds, while a girl with three brothers might find it really hard not to be the only girl anymore. "On the other hand, they might relish it. The point is, don't make assumptions."
Try to ensure your children stay together, she adds. "You might have a situation where your brother says he'll take your son and your mum, who lives just round the corner from him, would have your daughter.
"You can see it's tempting, but it can be really damaging for children to be split up at a time of trauma, when they may need each others' support more than ever."
Indeed, maintaining stability should come high on your list of priorities, she says. "When someone dies in a child's life, it's important for as much as possible to stay the same in the rest of their life.
"So while you might have a great friend who could take your kids on, but she lives at the other end of the country, it might be that your children would be better off with someone else back in their own town, where they can they stay at the same school and keep the same friendships."
Hannah Cornish, family solicitor at Slater & Gordon Lawyers UK, agrees. "It's less important with infants or very young children, but once children have embarked on school life, my advice would be to do everything you can to keep them there.
"When everything else has fallen away, the one constant for children can be their school – the teachers and the friendships."
Try to pick someone with similar values and parenting style to you, adds Cornish. "Being orphaned is about as unsettling as it gets, so you don't want them to have a huge culture shock on top of that. You want it to be as smooth a transition as possible."
Better still, find someone immersed in the same networks as you, she says. "Your in-laws might be wonderful grandparents to the children, but if they will struggle to get on with others in your children's friendship groups, it may be hard for them."
Consider age too. "Grandparents of children are a really popular choice as guardians, but think about the age they will be at the age your kids reach adulthood and whether they are likely to have the health and stamina to parent children in the meantime," says Cornish.
"It isn't ideal for a teenager to be find themselves living with someone frail and in their 80s, for example, although there will obviously be exceptions."
Don't stress about finances or the size of someone's house, though, she says. "You shouldn't rule people out just because you don't think they have enough money or bedrooms as you can take care of those problems with what you leave.
"You can even leave instructions for the provision of funds for your chosen guardian to build an addition to their home or move to a larger home to accommodate your children."
The support network WAY (Widowed and Young) is involved in lots of discussions around guardians. When one parent in the family has already died, it can feel particularly important to have a guardian plan in place – not just for you the parent, as now there's only one of you, but to the child who will probably be disproportionately fearful that you could die too, explains a spokesperson.
Kate Henwood, whose husband died of cancer in 2012, knows this only too well. "My 12-year-old son and I have discussed the guardian issue extensively so that we both know there is a clear plan that he knows is in place."
Henwood adds that your guardian choices may change over time. "We had guardians in place prior to my husband's death, but I've changed them now because that family lives a long way from us and has gone on to have children of their own, which has of course changed the whole family dynamic.
"I wanted someone closer to home and although it took me many months to make the decision, we've gone with my mum who, although 70, is young for her age and lives far nearer."
The bottom line, says Cornish, is that you will never find the perfect solution. "But if you consider what matters to you most, you will probably be able to make some reasonable choices. Remember instinct counts for a lot and that writing down the pros and cons can help."
Once you've made your decision – and remember it doesn't just have to be one family as you can have a plan B recorded too - remember to actually ask the people involved, giving them the option to say no even if they are flattered, and then get your wishes recorded in your will.