Hi everyone!
The textbook I’m using has just confused the hell out of me with a lesson that contradicts itself about when to use a and when to use para with verbs of motion like ir, vir, voltar or regressar.
Could someone explain this topic for me, please?
Many thanks 
K-so - here’s my take
‘a’ - when the movement is not permanent
‘para’ - when the movement is permanent
Agora, vou a casa e regresso este tarde.
Vou para EUA. Eu moro em Boston.
@Joseph - please correct!
Here is a screenshot of what my Portuguese teacher sent me.
I remember the difference by the duration of the movement. A is for short durations and Para for longer ones. A is a shorter word than Para, that’s how I remember the difference. The other uses for A/Para still confuse me sometimes (destination, directions…)
Yes, for movement, that’s the difference between the two. Thanks, @Paige and @stephencanthony. I’d just add that there is no specific cutoff point, in terms of duration, where you start to use ‘para’ instead of ‘a’. So, don’t expect consistency from one person to another or even for the same person.
Also, because of this vagueness, the duration that each preposition implies is quite context-dependent. For example, many people might say “Vou para a escola” (I’ll go to school) to say that they’re going to have a full day of classes (which is several hours), and then say “Vou à escola” if they’re just quickly dropping by, maybe to pick something/someone up or meet with a teacher (maybe one hour or less). On the other hand, if you’re going on vacation/holiday, you may choose to say 'Vou a [X place]", even if you’re staying for weeks. You’d say 'Vou para [X place]" if it were a permanent move.