[Gambas-user] what determines an application's resource useage

[M0E Lnx]

This question has been going around in my head for quite a while and
I'd like to get an answer.

How can I make sure that my application doesn't consume too much of
the system resources?
It is my understanding (correct me if I'm wrong) that if I assign a
variable in an application, the system will allocate a certain ammount
of RAM to that one variable (Ammount depends on the type of variable
that is declared)

Does that mean that the less ammount of variables used in an
application, the less RAM the application will use?

Any light in this issue is appreciated.

Again, Correct me if I'm wrong