What counts as a luxury? There are obvious answers, of course: we can probably all agree that diamonds and superyachts fall into that category. Other contenders might spark some debate. Holidays? A television? Caffeine?
Here's a more specific question: if you have a brain tumour, should it be a luxury to know you will always be able to talk to one person in your medical team who knows about brain tumours and - crucially – knows about your brain tumour and its impact on you?
We don't think so.
That's why we argue so passionately that all brain tumour patients, whatever their prognosis or the grade of their tumour, should have access to a neuro-oncology clinical nurse specialist.
But for some patients, that prospect is as distant as the most luxurious lifestyle.
When one neuro-oncology CNS took on a patient who had not previously had access to someone like her, she was surprised to discover one day that he had turned up at his local accident and emergency department with a problem related to his brain tumour.
She explained that she could probably have resolved the issue for him. All he ever had to do was give her a call, she told him.
His response? “I've never had that luxury before."
Our report on quality of life for people living with a brain tumour revealed that almost one in four of the patients we surveyed had no single point of contact for information about their treatment, never mind a named CNS.
In other words, there was no healthcare professional whom they could call without hesitation if they were bothered by changing symptoms or struggling with their emotions or worried about the prospect of surgery.
Lack of access to a CNS is often a problem for patients living with low-grade brain tumours whose consultants have advised a 'watch and wait' strategy.
If they are not referred for surgery, they may never come into contact with a CNS.
They might live for years under a cloud of anxiety without readily-available professional support.
We hear patients without a CNS describe their sense of isolation and their fear and – far too often – the lack of meaningful communication from their medical team.
And we hear patients who do have a CNS describe the relief of knowing that someone familiar, with relevant expertise, is there for them at every stage of their journey, easily accessible and approachable and fighting their corner.
It doesn't sound like a luxury, does it?