A simple plumb bob and a board with a line scored down the middle and a space cut in for the plumb bob to hang was what was used prior to the spirit level. Simple, reliable and effective but not as easy to store or carry. Also not so good at finding level except in the vertical such as for walls and such.
I am a simple man; I like simple. While I am slow to adapt to new things I can recognize when new things work better than the old. I made this when we first started to build the business after the war. It took me only a short time and I quickly put it to use building the stone foundations.
If it works why not use it. But there is a beauty to these new levels. I like the way they look and the simplicity in form and function is beautiful.