As Amberone said, it would be a challenge if I had to tell the police what I did on a particular day. I wouldn't have the faintest idea.
In detective fiction, including TV series, it always seems unreal to me when people are asked to provide alibis for a date and time that was weeks or months earlier. Obviously you would be able to remember what you had done on, say, the 7th of September between ten p.m and midnight if you were committing murder, but how could anyone else remember? Yet they always say something like, "I went out with Bill for a drink." "What time did you get home?" "About half past ten."
Unless I went out with Bill for a drink every night of my life and always got home by half past ten, there would be no way I could answer. But no-one ever stares blankly at the detective and says that they have no idea and can't even remember what they did yesterday.