I got off lucky and didn't start needing reading glasses until 46 years of age. And I don't need glasses for distance either.
I've only had to increase my reading Rx 3 times in the last 11 years. So I have been very lucky, most peoples vision change more often than that.
At home I keep a pair of those cheap readers by the phone just to use the phonebook, and one in the kitchen to read directions on a box, but I certainly don't use them for any amount of reading. They do in a pinch, but not much more.
First of all, in those readers , the lenses aren't of a very good optical quality, and the optical centers are certainly not in the right place, therefore, don't focus light onto the correct focal point of the cornea.
Also, not everyone has both eyes that need the identical correction. Mine have a difference between them.
So wearing those readers means one lens will either be too strong or too weak...causing fatigue very fast when reading.
When I want to read for any amount of time, I use the real ones, they are soooo much more comfortable for the eyes.
There is a huge difference in the visual comfort between real reading glasses made by prescription and the cheapie readers.
Do yourself a favor, and get the real thing after an exam, and use the cheapies on occaissions when you are stuck for a few minutes. Your eyes will thank you for it.