As someone who spent yesterday going through my storage closet I can honestly say that I found a few things had forgotten I had, even though I went through this stuff 9 years ago when I moved here. That's not "dementia". That's just having far more stuff than I can really need or can keep track of.
"Dementia" is believing things that aren't true or never happened, like claiming you won an election you really lost. Or believing everyone is out to get you. Or that everyone loves and respects your when they're laughing at you right to your face.