Is a lawyer really necessary?

Hi all, as my title puts it plainly, is an immigration lawyer really necessary to apply for residency? I am seeing just how expensive it gets and since I did DACA for my sister (first time) and always do my own renewals and get them approved, I am wondering if I can just do the whole process myself without needing to pay someone. Has anyone gone this route? If so, can you elaborate?

Thanks in advance.