Reposted from GameFAQs.com with permission from the author, HagFish:

In a fit of nervous energy, I tried to find my old playstation that last I knew had MR2 in it, but failed so attempted to see if MR1 would work on my emulator. Remarkably, I got CDs reading the way they should (my Grey Wolf is named "It works!"), so started playing the game again. I knew the ins and outs of MR2, even made an excel spreadsheet to make methods automatically (I could share if anyone wants), and quickly got bothered that I couldn't find an effective, cheap, no-lifespan-hits method anywhere. With a basic cheat addon program for my emulator, I pinpointed the addresses and discovered the mechanics of stress and fatigue. The item/food information was all posted on MRM long ago, but the fatigue amounts for various actions and the stress / fatigue limits for lifespan hits were never found (maybe just never posted). So, I've found it all, and here we go (I'm boring you, I know):

stress address: 800EBC79
light drill +3
hard drill +8
rest -8
1st barn upgrade -2/week
2nd barn upgrade -4/week
calm stone -5, 1st week of month only
potato +10
meat -10
mint leaf -50

stress warning (1st week of month only) at 40

fatigue address: 800EBC73
light drill +18
hard drill +33
rest -55
1st barn upgrade -2/week
2nd barn upgrade -4/week
fire stone -5, 1st week of month only
mango -10
taffy -50

very well 0
is well 1-20
seems well 21-40
seems tired 41-60
very tired 61-79
very tired, give rest 80-95
too hard 96-100

lifespan remaining (rolls over at 255): 800B88CC

Alright, now for the (hopefully) never-before-seen stuff: Take your fatigue and stress after taking an action, but before any items, foods, or barn upgrades change them.

If fatigue is 0-19:
No lifespan hits with 0-39 stress
1 lifespan hit with 40-59 stress
2 lifespan hits with 60-79 stress
3 lifespan hits with 80-99 stress
4 lifespan hits with 100 stress

If fatigue is 20-39:
No lifespan hits with 0-29 stress
1 lifespan hit with 30-49 stress
2 lifespan hits with 50-69 stress
3 lifespan hits with 70-89 stress
4 lifespan hits with 90-100 stress

If fatigue is 40-59:
No lifespan hits with 0-19 stress
1 lifespan hit with 20-39 stress
2 lifespan hits with 40-59 stress
3 lifespan hits with 60-79 stress
4 lifespan hits with 80-99 stress
5 lifespan hits with 100 stress

If fatigue is 60-79:
No lifespan hits with 0-9 stress
1 lifespan hit with 10-29 stress
2 lifespan hits with 30-49 stress
3 lifespan hits with 50-69 stress
4 lifespan hits with 70-89 stress
5 lifespan hits with 90-100 stress

If fatigue is 80-99:
1 lifespan hit with 0-19 stress
2 lifespan hits with 20-39 stress
3 lifespan hits with 40-59 stress
4 lifespan hits with 60-79 stress
5 lifespan hits with 80-99 stress
6 lifespan hits with 100 stress

If fatigue is 100:
1 lifespan hit with 0-9 stress
2 lifespan hits with 10-29 stress
3 lifespan hits with 30-49 stress
4 lifespan hits with 50-69 stress
5 lifespan hits with 70-89 stress
6 lifespan hits with 90-100 stress


One of the many interesting consequences? You can't do 2 hard drills in a row without something to reduce stress or fatigue between them and not take a lifespan hit. Anyway, I felt I may as well share some of my no-lifespan-hits methods, just for general enlightenment:

If you have the second barn upgrade, you can do hard drills on the 1st, 3rd, and 4th weeks of every month, rest on the 2nd week, give 3 mangoes on the 4th week before drilling, and feed meat. No lifespan hits, no money spent.

Or, if you have the second barn upgrade, calm stone and fire stone, you can do hard drills on the 1st, 2nd, and 4th weeks, a light drill on the 3rd week, give taffy on the 2nd and 4th weeks before drilling, and feed meat. No lifespan hits, only 150 G spent per month.

Hopefully this'll let people play smarter, and raise monsters efficiently without resorting to the brute force "feed taffy and mint every week" method. Sure, it's been a while, but it's still fun, am I right?