The Allies used four "types" of trenches. The first, the front-line trench, was located from 50 yards to 1 mile from the German's front trench. Then a ways back was the support trench, with men and supplies that could immediately assist those on the front line. The reserve trench was dug several hundred yards further back and contained men and supplies that were available in emergencies should the first trenches be overrun.
Then there were little trenches connecting them called communication trenches, which allowed movement of messages, supplies, and men among the trenches. Some underground networks connected gun emplacements and bunkers with the communication trenches.
German trench life was much different. They constructed elaborate and sophisticated tunnel and trench structures, sometimes with living quarters more than 50 feet below the surface. These trenches had electricity, beds, toilets and other niceties of life that contrasted sharply with the open-air trenches of the Allies.
"No Man's Land"
Both opposing sides begane to realize that it was much to dengerous in the day time, so attacks tended to take place just before dawn or right at dawn. Poison gases weremore effective in the mornings,because of the cool air and little wind the gases would stay closer to the ground for longer periods of time.
The men in the front line were mostly safe from the bullets, with an exception to the bigger shelling, during the day. When it turned dark they would conduct raids, venture out to get they lay of the land, or even eves drop over enemy lines to find out valuable information and pick up on some of the enemies strengths and weaknsses. .