Wasting money? I understand how you might feel that way. I lived in an outer province and did my own for 15 years. Sometimes, there were minor changes such as photo, or needing an extra copy of this or that.. nothing I couldn't do but required leaving Imm to find a copy place or whatever and adding a little extra time and paperwork.
Now that I live where there are agents, I am so appreciative that they do all the paperwork and certainly properly, for me. I know everything will be done perfectly w/o my involvement or writing my address here and there 10x... My total involvement is signing the completed forms as a young lady flips the pages for me and then showing up at Imm where my agent has already cleared approval and all I have to do is smile and I get my passport back.
All stress is removed.
For me, the fee for this is nominal and meaningless. I won't have to skimp on any meals.
ps - I choose not to change the oil on my car either. So, fr me and others, it is not wasting money but paying fro a service.