Yes I do have vivid memories of being in diapers/nappies 24/7 as a child and no it was mostly non voluntary for reasons of bed wetting and accidents during the day I was in diapers from the ages of one to five.
And it only became voluntary after the age of 6 although I didn't mind wearing diapers after that age because my brother was still an infant at that time and it felt natural to me to be in them as they kept me dry and happy at night/bedtime as Although my bedroom was right by the bathroom I still had the occasional accident at night, see below.
And yes to awnser your questions, I did wear diapers when I was born and up until I was 1 although I can't remember those years because I was too young what I do remember though is from the ages of 12-18 months on and after that so we are talking about the years 1981~1986, although I did wear them for a short time from the ages of 6~9 due to bed wetting accidents/relapses beyond my control.
During this time I wore many different brands from Pampers to Huggies and even LuV's however I mostly remember the pampers ones simply because they used to have a picture of a baby laying sideways on the box and where in pastal colours or stripes of gold/orange I wore pampers baby dry to ultra plus so I got to see the evolution of disposable diapers from my personal perspective in the 80's
I also had a younger brother who was in diapers from 1986~1990 as an infant so I shared the large value pack of pampers between the two of us,
As although I was potty trained at the age of 4-5, I still needed them at night time and at that time I was still small for my age so could easily fit into baby sized disposable diapers, however that's a subject I have already covered so I won't repeat myself.
I hope this helps awnser your questions.