This might sound bad, but I don’t use any as I don’t own a pillow. I currently sleep on just a mattress covered with a fitted sheet. For a pillow, I like my head slightly raised so I’ll just roll part of my blanket over and put my head on that, if that makes sense. It’s been doing the job.
I use two - one under my head and one between my legs/knees. I'm one who always falls asleep in a very specific position (left side, pillow between my legs, hands clasped around the pillow) then eventually rotate onto my stomach, and I usually keep my leg pillow pressed into my right side when it's not in use. I couldn't imagine sleeping without a pillow, but then again I glean a lot of comfort from soft, plush things and have kinda curated my bed/sleep experience with this in mind.
i use two for my head. i wish i had one of those adjustable beds where you can lift parts of it with a remote but those are expensive. i have a ton of decorative pillows though.
I use one for my head and other pillows for support when reading or writing. Sleeping is a different story. Some nights I sleep with as many as three, some nights I sleep with one, other nights I sleep with none. If its really cold, I usually sleep with a pillow. If its really hot, I usually sleep without a pillow or even a blanket. If I am sleeping on someone's couch I usually toss them all on the floor. I voted more than two just because of how irregular my relationship with pillows can be.
Two pillows (both for my head), but sometimes I sleep with one instead. Maybe 3 if I wanna put something between my knees, but I usually use part of my blanket for that.
I have so many. I had to line the far side of the bed with pillows because otherwise my dog rolls his way off the bed and gets stuck between the wall and bed at 2am. Other than the pillow fortress, I use 2. One to put my head on and the other between my arms.
Two regular-sized pillow for my head. Stress and eating spicy food will give me night-time acid reflux. As a result, I always have to sleep with my head propped up a bit.
I sleep on my side with two pillows behind my head and my leg over a long bamboo body pillow. One of my cats has taken to sleeping on top of said long body pillow
i mean there's technically four pillows on my bed but i usually only use two, usually the others end up on the floor , i feel like aesthetically my bed looks a bit sad with any less than 4 tho
i sleep with two. normally it's one under my head and one by my side (either to put between my knees or to bury my head/face into depending on the night). unless i'm sick, then they're both going under my head so i can breathe
I sleep on 1 (one) pretty flat pillow. If I'm staying somewhere that has big fluffy pillows then I'll just skip the pillow all together since I don't like my head being overly elevated. I do keep a second pillow on my bed if I want to prop myself up for reading or playing Switch but I never actually sleep with the second pillow.
I have a double size bed with two different pillows because I like choices. One is all nice, firm and supportive, the other one I can only describe it as a barely filled bag of cotton wool. Guess which one I usually sleep on, hint, it's not the expensive one
Hey, I also just roll a thin blanket underneath my neck, if that counts as zero. I sleep easily, whether on a mattress, floor or couch, so the lack of a pillow never bothered me. I got rid of mine when I began sleeping on the floor to improve my health and found that sleeping on your back doesn't require a pillow. Just some neck support and a simple rolled up object does the trick.
Technically three, but I only actually use two of them. I use a body pillow to prop my head up, and I have a regular second pillow vertically propped up against the body pillow that I rest my head on. I used to sleep with just the one regular pillow flat on my bed, but I had to sleep propped up for a while after my wisdom teeth removal, and laying down flat just never felt comfy after that for some reason. I prefer to sleep propped up now.
My third (and unused) pillow is the last thing one of my late kitties laid on before we had to rush her to the vets for the last time. I’m very picky when it comes to my pillows and it’s not flat enough for me to sleep on comfortably, but I refuse to get rid of it, so now it just stays on my bed untouched.
I sleep easily, whether on a mattress, floor or couch, so the lack of a pillow never bothered me. I got rid of mine when I began sleeping on the floor to improve my health and found that sleeping on your back doesn't require a pillow. Just some neck support and a simple rolled up object does the trick. 
