All rookie soldiers start with 40 Will and gain Will increases as they gain ranks.  They suffer a decrease in Will when they suffer a critical wound in battle.  Therefore, there isn't really a single low number to worry about, as it varies by each rank.  Also, a Squaddie (or any other low ranked soldier) who has been critically wounded can eventually gain enough Will back to be a successful soldier.

The table below shows the low and high Will values a soldier can have, by rank.  By checking each soldier against the table, you can determine if their will is too low for the rank they have.  I've included the low and high Will values for when the Iron Will upgrade has been purchased.  However, I'm not certain how helpful those will be, as you generally purchase that upgrade after your soldiers have been promoted a few times, so you won't expect to see values as high as the columns indicate.

I created the table using the following assumptions:


Each soldier gets a fixed +2 per level.
Each soldier gets a random +1d6 per level (iRandWillIncrease=6 in the ini file).
Each soldier gets another fixed +2 per level when the Iron Will upgrade is purchased (iBaseOTSWillIncrease=2 in the ini file).
Each soldier gets another random +1d4 per level when the Iron Will upgrade is purchased (iRandOTSWillIncrease=4 in the ini file).


(See http://wiki.tesnexus.com/index.php/XCOM:EU_DefaultGameCore.ini_settings for the ini values.)

                        Iron Will
Rank        L   H       L   H
Rookie      40  40      40  40
Squaddie    43  48      46  54
Corporal    46  56      52  68 
Sergeant    49  64      58  82 
Lieutenant  52  72      64  96 
Captain     55  80      70  110 
Major       58  88      76  124 
Colonel     61  96      82  138


The Second Wave options Not Created Equally and Hidden Potential change all of this.  Not Created Equally changes the starting Will from a fixed 40 to a random number between 25-60.  Will increases stay the same.  Hidden Potential changes the Will increases (and all other stat increases) to be random, so there will be a much larger variation of Will values among your soldiers.  The above table can still be used to check whether you have a soldier who is better or worse than "normal", though.

Source.

What's the maximum will a soldier can have per rank? How much willpower does an operative gain per rank?
I just ran into a nasty problem with an ISO download from Microsoft.  I successfully burnt it to a rewritable DVD, and copied the contents to the local hard drive on another machine, but when I went to run them they were corrupt.  It turns out the download had been truncated.

Now, OK, sometimes that happens - but it surprised me that the truncated file (which was only slightly more than 60% of the actual ISO) burnt successfully and seemed to be presenting me with a sensible file system, to the extent that I could (apparently) successfully copy the files.

So, is there some way I could have tested the file to see if it was complete or not?  The MS web site did not provide any information about the expected size, so I'm looking for a generic solution: given an ISO file which may or may not be truncated, is there some way to tell?  Do commonly used CD/DVD (data) formats include any embedded information about how much data is supposed to be on the disk, or even better, some kind of CRC?

A solution that detects most truncated images will be accepted, it doesn't need to be perfect.  (I'd prefer something that doesn't give false positives, though.)

[Addendum: a comparison of the disk burnt with the truncated image with the files extracted from the full image suggests that chunks of the data from many of the files were replaced with random information, perhaps from the contents of a previous burn to the same rewritable disk.]
