I do them in bulk, when i have bits of downtime here and there like waiting for water to boil. I use my phone to scan, and then move the photos
I try to be up to date by the end of each month because i also scan receipts and like having them for reference when looking over my spend for month. That said Ive still got some march notes to scan in. I dont review them at all in relation to scanning them. I am making a digital archive of things Ive written down for any reason. If it is not worth archiving then i can delete it later, which i often do.
What helped me most with becoming consistent with it was a few key things listed below - and the overall process can be picked up and put down whenever i feel like it without causing chaos
1) Respect the page. when taking the note, I do not assume context will exist for it later. If a stranger were to get a photo dump of all my notes, they have a reasonable chance of organizing them appropriately. Missing context is written on the page first before putting it away, like date, page number, header keywords
2) I scan everything with my phone
3) I move scans from my phone to a single 'destination' folder on my computer / cloud and delete from my phone.
4) Within the destination folder, I subfolder for items of multiple pages. Not categories or dates or anything fancy. Just a very simple grouping of page x of y situations. No thinking involved. Similar to a stapler
5) I move things out of that scan dump folder into my regular digital file organization as needed, if needed. Personally, I have a "Handwritten Notes" folder - and within that folder I have an "Unfiled" folder which is my scan dump location for #3. After Im done with step 3 I move everything up a level out of the "unfiled" folder
In general, most of my digital file organization is with shortcuts anyway, so at this point im done with the scanning process. I find getting things scanned is meaningful by itself, and i dont see the need to comingle my handwritten notes with my digital notes. shortcuts used whenever i want both types of things in the same folder