I'm guessing when most work was done by hand, nails would not have a chance to grow and need to be trimmed...
So when did the practice of nail (fingers and toes I guess) cutting/trimming start, and when did it become commonplace?
There's a whole section in the Popular Questions section about personal hygiene. Here's the bit about nail trimming. This link from there says that nail clipping/trimming has been around before recorded history.
I hope this helps.