Millions of people go without glasses all the time. I've been without them for over a month at one point. My eyes didn't correct themselves.
That's kind of consistent with my experience too because I've never noticed any change in that short of time. My eyes have been correcting themselves but at a slow rate. Only 0.25 diopters per year which is really hard to notice until you get an exam. One thing that is emphasized on this new site is that your eyes aren't likely to improve much if any if you don't challenge them by looking at things that are just slightly blurry and focus until they become clear. One thing that will supposedly prevent improvement is if you just let your eyes get used to the blur.
Also, the fastest they can improve is supposedly about 1 diopter per year which can seem really slow or really fast depending on your point of view I guess. When people's eyes get worse it's usually over a long period of time as well.
One thing about the millions of people that that go without glasses all the time is that their eyes don't keep getting worse. At least not on the scale of those of us who do a lot of up close stuff, reading, computer work, iphones, etc. Just my own experience but people I know who work outside, if they wear glasses at all, their prescription is very weak, like 1 diopter or less. Engineers I know usually wear at least 3 to even 6 or 8 diopters meaning they need glasses to read something right in front of their face. I'm closer to the latter at about 3 diopters.