system
Given the following post, respond as if you're commenting on Reddit:
human
[40k] Is it worth the Imperiums' time to try and save an injured guardsman?

Like say he got his arm blown off, would the Imperium try to save him? Or is it more cost effective to let him die?
gpt
This is, of course, very dependent on who the guardsman is, what regiment they're in, and (as a natural follow on from that) where they're fighting.  

Generally speaking, the Guard is well known for its high initial casualty rate.  Within the first 24 hours of battlefield action, a good proportion (estimates vary, but it can be as high as 50%) of rookies die.  Those people are less likely to be saved if their arm is being blown off: a rookie batallion will have comparatively fewer available medics, the soldiers are less valuable, and they're being sent in to soften the enemy up and probe for weaknesses anyway.  It's not that saving them is bad, it's just not necessarily practical.  These are very intense zones.

The people that survive become much more important.  Once they've gained a bit of battlefield sense, commanders tend to be more careful with them, might send them into less deadly zones with more support (might not, but rookies get treated worse overall).  If there is a medic there, and if they can stabilise the person, and if they can evacuate them, the guardsman might even get a biotic arm.  Probably not a very fancy one, but one fancy enough to operate a lasgun, to aim, fire, strip it down, and clean it.  For the wealthy, the Imperium has very nice augmented limbs.  That expertise trickles down, and as you rise in the ranks better options are going to become available.  

Warp travel is very unpredictable, difficult, and expensive in terms of logistics.  Recruiting another soldier is a link in the supply chain they don't want.  Replacing limbs is not as expensive.  Guardsman are cheap, but they aren't free, and for that reason they get patched up when it's practical.  Not normally practical for newbies, but for the rest it's more likely to be.  Some of the greatest heroes in the Imperium have mechanical body parts, and that includes Colonel "Iron Hand" Straken, and Commissar "Fuck-off Killy Klaw" Yarrick.  It's not a hindrance when you're really good at what you do.