Why? Because even though you're doing something you've done a ton of times and nothing has happened, just this once something WILL happen. Case in point. I went out this morning to feed the birds, as usual, and had to dodge the dried out and drooping branches on one of the hemlock trees. I had trimmed some of them earlier in the season and since it's been hot and dry lately, more have come down to get in my way. So...I got out the big trimmers and went about cutting branches. After a few, I was reaching up high above my head and went to cut the branch and some bark chipped off and fell into my eye. OW!
I got out all the little bits except one that was stuck under my upper lid. Lots of eye watering and blinking and pain. It finally came out later in the afternoon, but it must have scratched my eyeball 'cause it still hurts.
SO....just don't go out there and do the usual stuff. Save yourself a lot of pain and aggravation. Wear Your Safety Glasses!