I got (1) and (2)

Luckily for you (and unlucky for me since I have to manually transcribe it) I have the daily schedule of one Captain Geoffrey Bowen with the 2nd Battalion Lancashire Fusiliers on September 3rd, 1917. I'll be giving some context in brackets throughout for reading sake. I should note this is by no means the "average" experience as this is a higher level officer but it can give some context:

8.pm. Started [wake up]
9.30 p.m. Arrived. [at trench]
11 p.m. Company arrived.
11 p.m.-3 a.m. Round the line [ie: checking on men, checking positions, maintaining quality control across the line]
3.15 a.m.-4.15 a.m. Sleep
4.15 a.m.-6.am. Stand to. [Night watch, essentially]
6 a.m.-6.30 Reports [from lower level officers]
6.30a.m.-9. Sleep
9 a.m.-9.30 Breakfast: bacon, eggs, tinned sausage
9.30 a.m.-10.10 Round the line
10.10 a.m.-12. Reports, etc.
12.30 p.m. Lunch: Steak, potatoes, beans, sweet omelette
1.45 p.m.-2.15. Daylight patrol.
2.15 p.m-2.30. Sleep.
2.30 p.m.-3.40. Gup [gossip, idle chat] with the C.O. 
4 p.m. Tea, bread, jam.
4.30 p.m.-4.35. Sleep.
4.35 p.m.-5.10. Entertain 'Bowes' 
5.10 p.m.-5.15. Sleep.
5.15 p.m.-5.25. Trench Mortar Officer reports.
5.25 p.m.-6.15. Sleep
6.15 p.m.-6.35. Entertain Brain and Padre [Chaplains, implied work on mental and religious health]
6.35 p.m.-7.30. Sleep.
7.30 p.m.-8. Round the line
8 p.m.-8.15. Dinner: steak, potatoes, tinned fruit and custard.
8.15 p.m.-9. Round the line
11.30 p.m.-12.30 a.m. Sleep.
12.30-2.30 a.m. Intensive sniping [under fire]
2.30-5 a.m. Sleep.

We all talk about how horrible life in the trenches was and man, must've sucked to be those guys huh?! Do we really know what these men lived through? We are talking about thousands of years of cultural history in the West which glorified war and it being shattered in 4 years flat. Seriously, how traumatic would it have had to have been?

I never could stand shell--fire. I got into a thoroughly neurotic state during the day. Enduring a bombardment is the opportunity for that kind of nervous disease which made Dr. Johnson touch every post as he walked along Fleet Street. You think of absurd omens and fetishes to ward off the shell you hear coming. . .

So all the day you listened, calculated, hoped or despaired, making imaginary bargains with fate, laying odds with yourself on the chances of these various horrors. One particular gun would seem to be firing more directly on you than the others. You would wait for its turn so intently as to forget other perhaps more real dangers. At last it comes. You hold frenziedly on to the conversation; you talk a little too fast; your nerves grow tense, and while you continue to look and talk like a man, your involuntary muscles get a little out of hand. Are you knees quivering a little? Are you blinking? Is your face contorted with fear?

You wonder and cannot know. Force yourself to do something, say something, think or something, or you will lose control. Get yourself in hand with some voluntary action. Drum out a tune with your finger-tips upon your knee. Don't hurry - keep time - get it finished and you will be safe this once. Here superstition and neurasthenia step in. Like the child who will not walk on the lines in the pavement and finds real safety in putting each foot on a square stone you feel your ritual protects you. As the roar of an approaching shell rises nearer and louder you listen in inward frenzy to the shell, in outward calm to the conversation. Steady with those nervous drum-taps on your knee; don't break time or the charm is broken and the augury vain. The shell roars near. What was Thorburn saying?

"Oh yes!"[sic], the rations come up at nine o'clock, enough for twice our numbers."

This is a journal entry from one Charles Edmonds describing his experience with a single artillery shell he hears during a casual conversation and in my opinion perfectly encapsulates mood of trench conditions -- one of persistent, neurotic terror.

Many people like to bring up how men only served in front line trenches for about 7 days and would then cycle out to a rear trench to "rest" for a week or two, implying that life was cushy and more laid back than we think. They would generally not get such comfort, you did not escape the war and its horror. If you were on "rest" your job was generally to act as one of two jobs -- a runner or a supplier or in a worker party. A runner would have to run between communication trenches and the front line to deliver messages and vice versa. Since we didn't have trucks and armored vehicles of any kind all supplies would have to be delivered by hand. We're talking about food for tens of thousands of men stationed on the front line in a sector, and those on "rest" would have to do this.

As you approached the front delivering your steaks and rum and other rations it would likely be in the dead of night to shade you from snipers, which were a constant threat and you couldn't exactly be subtle lumbering around with goods. The darkness would not stop them from still popping off shots at you. The water would be knee high at least in more hot sectors and even up to the waist at times. It would not be that clear Hawaii water, it would be grungy, muddy, bloody water. You would have to negotiate these cramped, usually unfamiliar trench systems in pitch blackness all while carrying a couple dozen kilograms of rations while being under periodic sniper or machine gun fire. If you were in a "quiet" sector (ie: one of significant distance from enemy trenches) you replace "sniper" and "machine gun" with "constant artillery shells around you" and "offensive patrols."

Speaking of that, let's talk the life of a soldier on a front line trench. Your job, all day, was to fortify your trench. Refilling sandbags (which didn't use sand but clay) and packing them in defensive positions. You will note that by putting sandbags in damaged or unfortified areas you are inherently exposing yourself as you lay them down. It was very nerve wracking. You would be clearing water out of your trench, digging up bodies and burying them, dealing with the smell and defecation of all types, and hiding in tiny holes whenever artillery barrages occurred. That or hitting the deck in that aforementioned grungy, muddy, bloody water when a snipers shot snapped right above your head and you were pinned down. Or crawling out over the top to lay down barbed wire to replace damaged sections. Note how the enemy had offensive patrols specifically designed to hunt people like you down who were reinforcing barbed wire fortifications which at times extended dozens of yards or even hundreds of yards out.