This is the main reason I read nearly everything on my computer or e-reader. The Times print shrinks every year and so does the print on my physical books.
Books meant for e-readers work fine, since you can expand the text. PDFs read on them are terrible. When I produce a draft of a book I’m working on for an e-reader, which lets me read it anywhere, I use like 22 point font before saving it to pdf. Then it looks fine.
You can magnify the pdf file using ctl = (which I think of as ctl +) repeatedly. Demagnify with ctl -. With my 14" wide laptop screen and use 3/4" margins and 12 pt type, I can get essentially 24 pt type. Even more if you use horizontal scrolling (which is a nuisance).
Yeah, but the think becomes unreadable without moving things around. On a decent sized monitor or even a tablet, no problem.
This was not a minor problem - I had about 70 books to go through in pdf. The first year I judged this contest it was a nightmare, so I bought a tablet for the next year.