I often wear the gaiters shown in the photos GH posted and heavy duty hiking boots for off trail hiking through brush and tall grass primarily for protection from thorns, sharp ends of broken manzanita branches, prickly pear hidden in the grass, etc. These have even prevented stab wounds from agavi. However, protection from snake bite is still high up on the list of reasons I wear them although I've never had a snake encounter where the gaiters were needed. The risk of snake bite may not be that high but the consequences if bit, especially when off trail hiking solo in remote areas, makes me want a little extra insurance.
On the down side, the extra weight of the heavy duty boots and the gaiters definitely reduce my hiking range, especially in warmer weather. I never wear them when trail hiking or off trail in open terrain where it's easy to navigate around the prickly stuff and see/hear sneaky snakes.