Ship of Theseus

I have posted several answers about the obscene danger of World War II combat for the frontline infantryman;

• As a drafted soldier, am I more likely to return from war unharmed during the Civil War, WWI, WWII, Korea, or Vietnam?

• The men of Easy Company in WW2 had sometime away from the line, mainly in preparation for Market Garden. Are there any companies or squads that landed on D-Day and got no time "off" until the wars end?

• According to a History Channel documentary, during the Vietnam war, US ground troops would face 240 days of combat a year, versus 11 days of combat a year during WW2. Is this claim true?

• How often were soldiers in the US army during WW2 phased out for new recruits?

• Why were injured soldiers that had recovered sent back to different units in WW2?

Some men were lucky and survived the war without a scratch, while others were killed almost immediately.

The United States Army utilized a purely individual casualty replacement system during World War II. As casualties occurred, a (theoretically) equal number of men trained as loss replacements in the same or similar specialties would be requisitioned from rear area replacement holding units and sent forward. These men entered the Army from all over the United States and had no permanent unit affiliation until their final assignment. Once units entered the front lines, they rarely left except in exceptional circumstances; this was exacerbated by the Army's policy of raising a maximum of only 90 divisions (87 of which saw combat). The German system differed from the U.S. system in that Germany was divided into a number of military districts for purposes of replacement. Divisions were raised on a regional basis, and each division had in its home district replacement units which would train men for service in subordinate units of the division and send them to the front, where they would receive more formal training in the division's replacement receiving unit before going into combat. Men who were wounded and sent back to hospitals in Germany for treatment would return to their former units via the same process. The Germans, having raised several hundred combat divisions as well as a myriad of other unit types, had a habit of relieving battered units from the line regularly for rest and reinforcement. When things began to become tough mid-war, units were often ground into dust in place. New units moving into an area assumed the name and what personnel remained of the previous one.

• Were Americans who enlisted or were drafted during World War II able to choose the Pacific or European theater?

• How were elite divisions in ww2 such as the 101st airborne from Band of Brothers able to have replacements often even though training took 2 years?

• The utilization of older men by the Army, particularly in relation to the manpower troubles of 1943-1945

• It's 1943 in America and I just got drafted. Do I have any say in what job I do or what branch I serve in? Is my situation different if I am black vs white?

• Conscripted men in the US army generally aren't portrayed as any different from volunteer soldiers while in other countries they are shown as poorly trained, poorly armed, and with very low morale. Were conscripted units in America trained, armed and treated just as well as its enlisted men?

• Training of infantry replacements

• Did US troops in WW2 experience continuity of unit integrity as they progressed from basic training to combat?

• [American manpower situation during WWII] (https://www.reddit.com/r/AskHistorians/comments/4yrj2r/ww2_ive_heard_contradicting_reports_on_how/?)

In the U.S. Army in World War II, Infantry branch men comprised 81.9 percent of casualties in all arms in the European Theater and 93 percent of the casualties suffered in total in infantry divisions; 84 percent of the Infantry branch losses in the divisions were among riflemen and heavy weapons crewmen. While men in other units of the divisions such as Engineers or Field Artillery would be relatively fresh and ready for more action, the men in the frontline units (the twenty-seven rifle companies in particular) would often be well understrength, beaten down, and combat ineffective. The "tip of the spear" of the infantry division was its thirty-six line companies, comprising 6,651 men at full strength in mid-1944.

Table 5-9. Distribution of Battle Losses by Branch (Divisions)

Branch	Infantry division (percentage)	Armored division (percentage)	Airborne division (percentage)
Infantry	93.0	62.0	85.6
Artillery	2.4	3.6	6.9
Armor [includes Cavalry]	2.0	23.1	0.0
Engineers	1.5	3.3	3.9
All others	1.1	8.0	3.6

Table 5-13. Distribution of Battle Losses by Branch Within Corps and Larger Units in the Combat Zone as Percentage of Total Battle Losses [European Theater of Operations only]

Branch	World War II
Infantry	81.9
Artillery	4.5 (3.6 field, 0.9 antiaircraft)
Armor [includes Cavalry]	6.6
Corps of Engineers	3.2
Army Medical Service	2.8
Signal Corps	0.2
Quartermaster Corps	0.1
Ordnance Corps	0.2
Transportation Corps	Negligible
Chemical Corps	0.3
Military Police Corps	0.1
Miscellaneous	0.1

Company L of the 134th Infantry Regiment, 35th Infantry Division received about 3.4 times its original complement (193) in replacements (663) during its service in the European Theater from July 1944 to May 1945. Only 11 original members of the unit did not become some type of casualty.

Month	KIA	DOW	SWA	SIA	LWA	LIA	MIA	POW	Sick	NBC	Total
7/44	37	3	16		111	5	1	6	6	10	195
8/44	9	1	7		36	6	3		15	3	80
9/44	15		2	1	30		3	13	2	1	67
10/44	3				3				3	2	11
11/44	24		12		124	8	1		20	43	232
12/44	8		13		46	7	22	89	14	3	202
1/45	6		3	2	16	21			14		62
2/45	2		2		6	3			10	1	24
3/45	1				28	1			6		36
4/45					4	1			9		14
5/45									2		2
Total	105	4	55	3	404	52	30	108	101	63	925