Boots, and all footwear, should be as light as possible. One workplace said I had to wear steelcaped boots, so some days I wore them and some days I didn't. The days I did I was knackered at the end of the day due to having (cumulatively) lifted hundreds of kilos throughout the day. It's bad enough walking miles through the bush
without lifting extra kilos as well. If I want extra kg's I'll carry the .357.