Distance

Hi Ricky,

Yes, I understand your struggle. There is a general rule (very general) to use este, ese and aquel. Este is pretty clear because it works exactly the same way as "this" in English. But when it comes to differenciate between ese and aquel, the "general rule" is to use "ese" for what in the mind of the speaker is a "mid distance" and "aquel" for what in the mind of the speaker is a "far distance". You can see that it can be subjective to each individual/speaker. It might help to think that "aquel" is generally used to point at something that is out of reach, so you would have to stand up or move to be able to touch. 

On the other hand, a more specific rule applies when we consider the demonstratives inside a conversation between two people. In this case, the use of este, ese or aquel is the following:

1. este, to refer to something/someone near the speaker.

2. ese, to refer to something/someone near the listener.

3. aquel, to refer to something/someone away from both the speaker and listener.

To give you a very simple example:

Imagine you and I are talking. We are opposite each other. You have a book in your hand. I would say "Ricky, ¿ese libro es interesante?" 

I am using "ese" because the book is in your hand, so it is near you (in your "territory").

You may reply: "No, este libro no es interesante". 

You now use "este" because you are now the speaker and the book is in your hand, near you.

And you continue saying "Voy a leer aquel libro de allí, porque creo que es más interesante."

You are using "aquel" now because you are pointing at another book that is out of reach from both of us, on a shelf.

I hope this clarifies a bit your doubts. But, going back to your initial question, no, unfortunately there is no "set" distance to use ese or aquel. Like I said, it is a bit subjective.

Saludos

Inma