Grog said:
*sigh*
It's like I'm not even here....
Sorry, mate. I had written my post earlier, but forgot to click the post button.
As for your point, I respectfully disagree. Your estimated 50,000 man army costs a minimum of 15,000 gp a day in wages, according to the hireling prices in the SRD. Mind you, that's just at minimum wage.
For a 30 day campaign, each soldiers wage comes to 9 gp. The cheapest price in the thread has this item at 900 gp, so that's 100 soldiers left behind per healing zapper you bring. March with 45,000 troops instead of 50,000, and any disadvantage you have in the first encounter is made up for by the fact that you can heal up in 30 hours.
At 9k per, which is closer to where most people price it in this thread (and convenient for math), you won't be able to heal your whole army (you'll have 5 of the things, which will be too slow).
But, during a day of combat, you can completely heal 200+ casualties, who were dying and would ordinarily take a week or more to recover, so they are all back on the battlefield that very day, and another 200-400 in the night. Now one might say "but just hire the 5000 guys instead of healing 600 guys a day, and you'll win out until the 10th day, after which the first day of casualties will have healed anyway." This is true in the numbers as written, but remember we assumed a very short campaign of only 30 days, we aren't budgeting for feeding and equipping soldiers at all, and we haven't paid for a single person other than a 1st level mercenary.
Factoring these things in, the savings in reducing the army size by 10% allow you to heal more like 600 troops a day (and another 600-1200 at night), plus, the savings increase the longer the campaign.
It's not the perfect army solution, but I think it would have a signficant impact at the lower end of the cost spectrum.
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gnfnrf
EDIT: Removing errant zero.