Remember going to the old, small, hot, smelly, overcrowded room before the new building. I was using an agent and was told to arrive 3pm. Sat next to guy and started chatting. He said he had been there since 5am to get a number. I said I use an agent. He quickly commented he would never waste his money on an agent. At about that time, now a whole 15 minutes after I had arrived, my name was called and I collected my passport and was finished for the day. I did say as I walked past him that sometimes worth paying an agent.
On another note I went last week to get a re-entry permit. I know they can be done at the airport it's just I like to be prepared. Car park across road was packed and obviously immigration was too. I was in the "document check" queue for nearly 90 minutes but fortunately first when I went inside so only another 10 minutes.
Not complaint just saying.