I think what I'm asking is not posible, but...
I have a lot of forms already created and in use (16). All of them have similar fields and different ones.
My question is if I can re-use the same conditions based on a field, because I've to do the same job a lot of times (7 conditions in each form). Is there a way I can do this?
No, you cannot copy conditions from one form to another. However, you can clone a form and the conditions on that form will also be copied.
Right click on a form on My Forms page to clone it.