Is it better to say yo camino or simply camino?
This means that we do not need to use them because doing so is reduntant.
Why? If we look at the verb in our example at the beginning, caminar... yo camino, the ending -o of the conjugation is quite self-explanatory as to who the subject is, the same in the case of TU.. caminas or NOSOTROS caminamos.
This wouldn´t be the case for EL, ELLA, UDS, ELLOS, ELLAS, where the form of the verb (conjugation) isn´t clear enough by itself to explain who the subject is, so it needs to be accompanied by either one of these pronouns or a name.
Unclear: Habla todos los dias.
Clear: Ella habla todos los días.
Now, there is a time when we DO need to use pronouns YO, TU & NOSOTROS, and that is when we specifically want to emphazise and distinguish the person performing an action.
YO compro los boletos, y TU las palomitas, ¿va?
I´ll buy the tickets and YOU buy the popcorn, deal?


