I don’t use a notebook and have done fine over the years - for those of you that are reading this and getting anxious you’re not doing your job the “right way”. I don’t have a particularly prodigious memory.
I’ve sometimes thought there’s a value to forgetting. If it matters I’ll learn it through repetition, like compression almost. It always seemed like reconstructing things from first principles saves brain space and allows for generalisation and creativity.
Absolutely agree, I do use notebooks but like you say I dont think I need to at all, for some reason I just have some natural drive to write things down (plus I like notebooks). But I've often had experiences of reading through old notebooks and finding that the things I care about in there I instantly remembered without having to read the page, and the things I'd forgotten about I didn't care about anymore.