Occasionally forgetting something is normal with aging. What is concerning is a pattern of increasing forgetfulness, difficulty with familiar tasks, or getting lost in familiar places. A doctor can rule out treatable causes such as sleep deprivation, thyroid problems, or depression, and checking early gives a sense of control over the situation.
The difference that really matters: occasionally misplacing your keys or briefly not being able to recall a name is simply part of getting older. What you should watch for is a pattern in which someone increasingly forgets things they recently learned, starts struggling with familiar tasks or words, gets lost in well-known places, or where the people around them notice a change that also appears to be getting worse.
If that pattern is present, a visit to the doctor makes sense, but not because it is necessarily bad news. Some causes of memory problems, such as lack of sleep, thyroid problems, a vitamin deficiency, or depression, are perfectly treatable. A doctor can rule those out or address them. And if what is known as mild cognitive impairment is involved, a stage beyond normal ageing but not yet dementia, that does not lead to dementia in everyone. Some people remain stable for years.
Getting checked early therefore gives you a degree of control, even though there is no cure for most forms of dementia. You then know where you stand, treatable causes are not missed, and if necessary you can think in good time about what you want to arrange.
Moderate evidence, 1 source(s); the direction is likely but not firmly proven.