How Many - I carry either 3 or 4 everyday.
What I carry - My EDC (literally) folders are a Buck 482, RFP and a Buck 484, LFP. I have 1 or 2 fixed blades with me every day. On a 1 fixed day, when I am going to town, it's a Kabar 1232, RH carry. On the farm or out hiking/camping/hunting, the fixed blades jump to 2 on me, plus other cutting tools in a pack or the truck. These fixed blades are one of my Kabar 1219C2 variants on the right and a Becker 2/7/9 on the left. The knives vary depending on what I'm doing that day and the weather conditions.
Why I carry that many - I always have a minimum of 2 knives, one one the left side and one on the right. The reason for this is that if you are carrying something in your right hand,or get your right hand/arm engaged in some restricted endeavor, and your only knife is on the right, you are screwed. Hence 1 knife for each side, minimum.
Why do I carry 2 FIXED blades on the farm? You never know when you will need one and which side you will need it on.
This goes back to my first fixed blade. My Grandfather got his left shirt sleeve caught in some machinery. He reached down with his RIGHT hand, pulled out his Kabar 1232 and cut his sleeve off before his arm was caught in the gears. He looked at me and said "That's why you carry a fixed blade. It's always ready to cut." I asked him "What if it had been your right arm caught?"
After a moment, he turned off all the machinery and we went to town and he bought a second fixed blade, a Western L46-5. When the store got some more Kabars in, he replaced the Western with a second 1232 and gave me the Western, saying that if I was smart enough to come up with that question, I was old enough to carry a fixed blade." I was probably 11 or 12 years old. I can't remember if it was when I was in 5th or 6th grade. That started my love of fixed blades in general, and Kabars and Westerns, specifically. I still have that Western in my sock drawer.
That's the reason I carry a 1232 most days - big enough to do the job, small enough to not freak out normal people and something to remember my grandfather by every time I use it. And why I carry TWO USER FIXED BLADES in the field.