• Andrew McFarlane. Picture: Robert Perry
This could mean that either Sarah is either an extraordinarily considerate daughter, who feels that she has to inform her mother of her every move. Or, as is the increasingly common – and in this case accurate – explanation, she is one of a growing number of young-ish people who for one reason or another find themselves living back at home with their parents.
In Sarah's case, being sick of living alone in a studio flat – which was leaving her struggling to make ends meet – combined with the chance to save a bit of money for a deposit, lured her back home.
She had concerns. Would she have to account for her every move? Would she be able to come and go as she pleased? But a few minutes with a calculator and her bank statements easily assuaged any worries.
"And anyway," she reasoned, "it's not for long. I'm only staying until I've got enough money to get a better place of my own."
When the Office for National Statistics released figures showing that at the end of 2008, almost a third of men and a fifth of women between the ages of 20 and 34 were living at home with parents, eyebrows were raised. The ONS suggested that higher property prices, unemployment and people choosing to continue their studies were likely to be behind the trend. Others hinted that it might be because parents were being too soft or young people too lazy.
Whatever the causes, there is little doubt that when 1.8 million men and 1.1 million women are living with their parents – many of whom are in their late twenties and early thirties – what we once understood as the process of growing up and becoming independent has changed significantly. The question, though, is whether that is good or bad?
According to Shiv Malik, a 29-year-old journalist who has co-written Jilted Generation: How Britain has Bankrupted its Youth, which comes out next month, the implications of people being stuck at home for longer are serious.
"Of course it's a bad thing," says Malik. "Ultimately the phenomenon that we discovered is that people of our age are postponing adulthood.
Staying at home is just one of the ways that they do it." Malik agrees with the ONS suggestions that financial reasons are the main reasons that people stay at home, but for him the concerns it raises are social.
"Living at home causes a lot of frustrations in terms of forming relationships and having a partner and actually getting on with starting your life. Settling down, getting married, having children – none of these things can start if you can't even move out."
Andrew Macfarlane, 25, lives at home with his parents in Bearsden, Glasgow. He's lived away from home twice already, once in Hong Kong for a year and then for five months in Japan. But while he was at university studying for both his undergraduate degree and his Masters he lived at home. So does he like it?
"Not hugely, no," he says. "It's purely financial. I went to Glasgow University and because I lived so close, only half an hour away, there was no chance of getting into halls, and my parents didn't want to pay for me to rent a flat. So it was either get a full-time job and pay for it myself or stay at home. That's the option I chose."
Macfarlane says that although he's always got on with his parents and it has got easier to be at home as he's got older, there are still tensions. "When I was doing my undergrad degree everyone else lived with friends or in halls and they had much more freedom than I did. I had to account for my whereabouts – send texts saying where I was going and who I was with. I don't have to do that any more but there's still an expectation, 'Are you coming home for dinner? If not where are you going?' Even at 25 that hasn't got better."
That said, Macfarlane acknowledges that there are also positive aspects to living with his parents.
"I've lived with friends and with strangers and the good things about living at home are not the things that you might expect, like laundry and food," he says. "Not having to worry about bills is a good thing.
Not having to divvy up chores and tasks with flatmates and worrying about if people are doing their share is good too. I'm very clear about what I'm expected to do and what mum does and what dad does – I've had 25 years practice at it. Everything gets done and nobody whinges about it."
Ask Macfarlane if he's felt a stigma about still being at home in his mid-twenties and he says no. But then he offers a qualification. "I guess with friends who know me I get to say I'm back at home rather than I'm still at home, which makes it sound slightly better," he says. "I think had it been still living at home I might have been less confident in saying it."
For Alan Hogarth, 24, the situation is different. He has never lived away from home and as a PhD student at Strathclyde University studying part-time, he knows it could well be a long time until he does. Sharing a home with his mum and dad and his younger sister, who is also at university, doesn't worry him, he says. Even if, had he the money, he'd quite like his own place.
"I have my own space and I get on with my family so it's not a big problem. The main reason that I stay at home is financial but it's convenient as well as it's just outside of Glasgow."
Hogarth says that among his friends it's common to live at home, especially for people who have just finished a degree and are looking for a job. For them, he says, things are tough and recent figures concerning graduate recruitment suggest it's not likely to get easier any time soon.
Graduate unemployment is at its highest level for 12 years and according to the Higher Education Careers Services Unit (Hecsu) it's a situation that's likely to get worse before it gets better. "I've always been prepared for the fact that I'll have to stay at home while I'm doing my PhD," says Hogarth. "I'm funding it myself so I know that I'll be here until I find a job."
Was it discussed, I wonder, when he was making his decision to stay on at university, or was it just an assumption that he could stay at home for as long as he needs to?
"There wasn't a conversation about it. I just knew that my parents would be supportive no matter what I did. I think they like having me here as well."
And it seems that's not an uncommon sentiment for twentysomethings who are still living with their mums and dads. For Hogarth he knows that when his older sister moved out of home – she now lives in Germany – his mum found it hard. For Macfarlane, the fact that his mum is now retired means that she is glad to have him around.
"If I didn't live there, mum would be at home by herself and it would be lonely for her. I was down in London earlier in the summer and she felt that loss. She likes having me around, not just for that, but because there's a familiarity about it. And for my dad, he gets to talk about things that my mum might not be interested in. He gets another guy in the house and she gets her son."
Neither Macfarlane nor Hogarth pay rent to their parents. For Hogarth, he's clear that his parents understand that his financial commitment is to his study. The issue of rent never came up. For Macfarlane, it was an issue he talked about with his parents but as far as he's concerned, and this is what he told his parents, if he had to pay rent he'd rather live in a rented flat. In both instances, it seems, living at home works for both children and parents, but it's not always the case, at least financially.
In a survey of 1500 parents, Trust Fund provider The Children's Mutual revealed that nearly one-third of parents are remortgaging their home to financially support their grown-up children. Two-thirds of those asked said that they have had to or will have to reduce their day-to-day living costs in order to afford supporting their adult child.
However, according to Shiv Malik, looking at what parents have to give up misses the point that their children are being denied support that for previous generations was taken for granted.
"The notion that somehow parents are too indulgent is an awful myth," he says. "It's so patronising – the argument being 'when we were young we moved out in our early twenties and by the time we were in our late twenties we had children'. We looked at all of this to answer the question:Is it harder to do all of this now. If it is, then it's not simply the case that we're lazy. It turns out that across the country it's incredibly hard to buy a house – far harder than it's ever been at least since the 1950s. And when people can buy they're getting smaller, pokier houses which means you can't even start a family even if you do manage to buy somewhere. The attitude of 'kick them out and they'll learn to stand of their own feet' simply isn't right. It's not true.
Our parents' generation were given a whole load of help to start their lives that we don't get."
So how does he explain the fact that at least for some, living at home for longer seems to work just fine?
"Our generation (people in their twenties] isn't terribly political and they are willing to put up with a lot. If they knew that it doesn't have to be this way, as in there were times when governments built houses and allowed people in their twenties and thirties access to affordable homes, then I think they'd be a lot more annoyed than they are now and they wouldn't just think that it's their fault or that they don't work hard enough or they're just unlucky."
Hogarth often talks with his girlfriend, who also lives at home, about getting their own place, but they know it's unlikely. For Macfarlane, though, things are about to change.
In October he will not only be leaving home, he'll be leaving the country. He's got a place to study for a PhD at Canterbury Christchurch in New Zealand. So is he looking forward to moving out of his parents?
"Absolutely. I think I'm looking forward more to that than the PhD.
Having my freedom back and not having to account for myself to anybody. I'll be able to go where I want, when I want, with whom I want."
And who wouldn't want that?