The last time we renewed our passport, we didn't need to go to the DFA. All you had to do was fill-up the necessary forms and submit 3 pieces passport picture and send it there. After a few days, they send the new passport along with the old/canceled one.
Now, you have to appear before an authorized DFA personnel in the DFA office to sign and give your thumb marks. So naturally when you get there, there's a process involved in the filing of passport renewal. You have to stand in line because they need to assess each and every individual and so if you're late, then its a long wait.
My mom, Bugz and I were there at 8:30am sharp to meet up with the travel agent who helped us arrange the papers and forms needed for the passport renewal. It was really so much easier when you have an agent to help you with these things. It only took us less than 15mins to get in line, sign and give our thumb marks. Except for the photos, which we needed to retake because the ones we got were rejected (stupid studio...never again!), everything went smoothly.
We may have paid a little extra for the help but it sure beats standing in line for hours.