My DD had acid reflux, so we had major puke problems, and explosive nappies. In the first 3 months we often got through at least 2 sets of clothes during the day (dress / top and leggings), and a babygro at night. She had a clean vest on each morning and night, and any time we had to change her clothes.
As she was sick so much in the beginning, I had a constant supply of muslin cloths and towels to hand. I would cover myself in a bath towel when I was feeding her (I got soaked once or twice), and cover her with a muslin cloth/bib as much as possible.
As others have said, people will often buy you cute outfits/babygro's. While I was pregnant I made sure I had a sufficient number of vests (14 in each size unless you want to do washing every day), muslin cloths (I had 20), and sheets for the moses basket/crib/cot. These are things people don't buy you! Ooh and socks - buy 00 size if you can-this is newborn size (I also suggest "sock-ons" - brilliant invention!!)
Just a tip, most baby clothes we bought I swapped for larger sizes as tend to use gro's early on. I'm so glad now. Baby is in 9-12 month clothing and only seepven months so its saved me from buying too much
With DC1, it was about 2-3 in 24 hours and about 8 nappies in 24 hours. We had poo leaks and little milky pukes which went underneath bibs. Actually, DC1 wasn't too bad and some days it was 1 babygrow in 24 ours..You do need to soak or rinse off the vom quite quickly as it can stain.
I find this SO confusing! I've tried to calculate what might be the baby's minimum needs (How many newborn clothes do I need?) but I feel like my figure is way off? Also, did you start with newborn sizes or go straight to 1 month?
I'm pg with DC4 and I still couldn't accurate predict how many you will need, although IMO over run with clothes is a better position to be in.
I will have a little pile of baby grows upstairs, another downstairs, a couple or 3 in my changing bag and a little pile by my bed for middle of the night changes. I also keep a bag of spare clothes in the boot of the car for potty training accidents and car sick incidents so there will be some in there too.
I make sure that I have enough to last long enough that we don't run out if I can't get the washing machine on every day. I also buy a bit of a larger size as they can sometimes shrink in the tumble dryer.
However I can predict that my little newborn will: Have an 'all up the back as far as the neck explosive poo' when he is wearing my favorite outfit, or when we are just about to leave the house...or both, or when he is on the lap of a guest who is dressed nicely! I will also have days where I will look at the pile of laundry that has been created by the smallest member of the household over the last 24 hours and think...how???