the only docs I attached with I-130 was 2 passport size of my pictures and my husband, birth certificates for both, his fathers passport, his passport and mine passport 1st and last page photocopy, marriage certificate. if your spouse is out of country and the birth certificate not in English make sure you translate that and also attached the original as well

I am and up to now everything is fine. If you have patient you can do it by yourself. The chart flow at USCIS is very detailed about each process and they have all the info you need about evidence examples and other things.

we did everything by ourselves without a lawyer, it's easy, just follow the steps

in my experience I regret not getting a lawyer earlier when I started the applications myself and for that I think I’m waiting extra to get a final decision

We did it with a lawyer but added pictures (around 20, with friends and family), bank statements (we had a common Bank account), pictures of our passports stamps showing that we traveled together to different countries and documents from the hospitals as unfortunately we had 5 surgeries in 2 years and we accompanied one another (and we needed these docs to justify our absences from work so we had them).