We all need reminders for everyday tasks and events... birthdays, meetings or perhaps an appointment at the doctor's.
But Ricky Dean's memory problems are so severe he has to be told to do just about everything, from eating to brushing his teeth.
And just like Guy Pearce's character in the film Memento, he is constantly surrounded by lists and boards to remind him what to do. His iPhone is also invaluable in making sure he meets up with his friends at arranged times.
Not only are future events a problem, he also struggles to recall the past as he has no concept of time.
Ricky, 19, was starved of oxygen when he was born and later diagnosed with autism. Doctors say there is no name for his condition and despite his problems he has still gained five GCSEs (the UK's equivalent to the Higher School Certificate).
"It can be very difficult at times, but my family and friends are so supportive," he said.
"My mates are constantly having a joke about it, which is good, telling me I borrowed a tenner from them the week before. I can never remember if I have or not, so I make a list and if they're just winding me up I get my own back.
"My condition can be so frustrating for people, especially if they don't understand that I just don't remember anything to do with time.
"If I didn't have my lists, telling me to brush my teeth or have lunch, I would be lost.
"The worst thing is missing appointments with friends and forgetting good things. I can't look forward to anything, because I have no concept of time."
When Ricky, of Taunton, Somerset, was 11 his parents took him for a full memory scan which revealed the full extent of his memory loss.
Until three years ago, Ricky rarely left his family home, because he could never remember where he was going, but now relies on his iPhone.
Mother Nicki, 46, said that they "knew something was wrong when he was seven. To get a diagnosis was a relief because we had been saying all this time that he wasn't doing all these things because he wanted to.
"We try to promote independence but tasks such as cooking or running a bath present too much risk, because he wouldn't know whether the oven or bath had been on for five hours or five minutes. He has come so far and is an inspiration to others."
Now Ricky, who took five years of one-on-one tuition to complete his GCSEs, is studying agriculture and horticulture.
"Ricky is one in a million million as far as his brain injury is concerned" father Gary, 40, said.
"It is a mixture of symptoms of autism and memory issues that make him unique. For a time we thought he was suffering from food allergies, but we got him diagnosed with autism.
"It takes absolutely nothing to distract him from a task. Even a thought will stop him dead in his tracks but he has empathy for others and will help old ladies."