When looking at Smogon's analyses I found most of the HP spreads fairly random. I think we can allow us to be a little bit more efficient in following some simple guidelines.
SR, Spikes, Leech Seeds, Sandstorm, Hail, poison, burn; almost any kind of passive damage falls under the "sixteenth part" rule, so does Leftover and Black Sludge and other healing abilities like Rain Dish and Poison Heal. The damage or the healing increases for every sixteenth of your HP. Still, many player tend to put maximum HP on their walls, some people hit the sixteenth exactly.
I dare to say: Both ways aren't perfectly efficient - though latter ones are on the right track.
Because the damage will be round down when you don't hit the sixteenth, actually you should exceed the sixteenth by one health point. It allows you to survive one more turn without wasting EV in HP. One pretty blunt example: A SR weak one without Leftover actually can switch in four times without dying (that's secured with the "keep your HP in odd numbers" rule, too, but more later).
Those are some of the magic numbers: 305, 321, (337), 353, 369, 385, 401, etc.
However, there are three expections: 338 HP, and 404, 405 HP.
First one is to survive Seismic Tosses and Night Shades one more round than usual. Mons with 338 or more HP plus Leftover will survive five Tosses with only 1 left; of course this number is even, so you will build up fewer substitutes but in that case you are fine with 337 anyway, because you won’t get hit directly. 404 is for those base 100 Mons, who can form 101-subs but can’t exceed 404. If you don’t want to sub, 401 is fine but 405 HP is better for those who want to and can have that much HP as it allows more subs. From this we can conclude to next rule.
Keep your HP in odd numbers I have mentioned before: That rule applies to any situation the "fourth part rule" is; to SR weak Pokemon and to Substitute user. Having an odd number of HP allows them, to switch in more or to build up more subs (four times without leftover), with only a mere part of their health left.
There is an expection: if you want use stat-raising berries or want to trigger abilities like Blaze and Swarm, you can and should keep your HP even because taht way your berry/ability will be activated after you have lost 3/4 of your HP, ergo after three instead of four subs.
Often the second rule is covered by the first one, but some player carelessly put one HP in some glass cannons. One more point actually can cause more trouble occasionally than help; minimal, but present - better put it somewhere else, because the damage can be much more crucial when using Life Orb sweeper.
The Life Orb introduced in the 4th gen is a bit odd, because it doesn't work with the "sixteenth part". As it lowers your HP every round by the tenth part of the maximum, you may have expected it: having a zero at the end of your maximum HP can't be good. If you follow the second rule, you won't have problem; many Life Orb run minimin HP, so at 31 IV it shouldn't cause troble anyway.
There actually are some Mons in this meta those minimum HP is XX9, those, whose base HP has a four or a nine in the end (74, 79, 84, 89, 94, etc.): Ferrothorn, (Thundurus), Empoleon, Landorus, Golurk and Amoonguss.
From those only Thundurus (now uber), Landorus and Empoleon (UU) may run Life Orbs. Good, that the Smogon analysts put the remaining four EV in something else than HP to keep the Life Orb recoil low. For those who accidently do that, here again: Better don't dump the last for EV into HP.
Coclusion:
1. The optimal number of HP exceeds the sixteenth part by one.
2. Having an odd number of HP allows one to lower 1/4 of one's HP (via sub or super effective Stealth Rocks) more often without dying than having an even number.
3. Life Orb user shouldn't have their HP being a divider of ten - a rule only for Thundurus and Landorus (and Empoleon occasionally).
Special sitiations:
- Having their HP at 338 or higher plus Leftover makes you survive Seismic Toss and Night Shade five times instead of four times.
- 405 is the optimum for those who want to create 101-subs.
- Alls those base 100, who want to create 101-subs, have to use 404.
- If you want to trigger berries or abilities like Torrent and Overgrow should use an even number of HP.
SR, Spikes, Leech Seeds, Sandstorm, Hail, poison, burn; almost any kind of passive damage falls under the "sixteenth part" rule, so does Leftover and Black Sludge and other healing abilities like Rain Dish and Poison Heal. The damage or the healing increases for every sixteenth of your HP. Still, many player tend to put maximum HP on their walls, some people hit the sixteenth exactly.
I dare to say: Both ways aren't perfectly efficient - though latter ones are on the right track.
Because the damage will be round down when you don't hit the sixteenth, actually you should exceed the sixteenth by one health point. It allows you to survive one more turn without wasting EV in HP. One pretty blunt example: A SR weak one without Leftover actually can switch in four times without dying (that's secured with the "keep your HP in odd numbers" rule, too, but more later).
Those are some of the magic numbers: 305, 321, (337), 353, 369, 385, 401, etc.
However, there are three expections: 338 HP, and 404, 405 HP.
First one is to survive Seismic Tosses and Night Shades one more round than usual. Mons with 338 or more HP plus Leftover will survive five Tosses with only 1 left; of course this number is even, so you will build up fewer substitutes but in that case you are fine with 337 anyway, because you won’t get hit directly. 404 is for those base 100 Mons, who can form 101-subs but can’t exceed 404. If you don’t want to sub, 401 is fine but 405 HP is better for those who want to and can have that much HP as it allows more subs. From this we can conclude to next rule.
Keep your HP in odd numbers I have mentioned before: That rule applies to any situation the "fourth part rule" is; to SR weak Pokemon and to Substitute user. Having an odd number of HP allows them, to switch in more or to build up more subs (four times without leftover), with only a mere part of their health left.
There is an expection: if you want use stat-raising berries or want to trigger abilities like Blaze and Swarm, you can and should keep your HP even because taht way your berry/ability will be activated after you have lost 3/4 of your HP, ergo after three instead of four subs.
Often the second rule is covered by the first one, but some player carelessly put one HP in some glass cannons. One more point actually can cause more trouble occasionally than help; minimal, but present - better put it somewhere else, because the damage can be much more crucial when using Life Orb sweeper.
The Life Orb introduced in the 4th gen is a bit odd, because it doesn't work with the "sixteenth part". As it lowers your HP every round by the tenth part of the maximum, you may have expected it: having a zero at the end of your maximum HP can't be good. If you follow the second rule, you won't have problem; many Life Orb run minimin HP, so at 31 IV it shouldn't cause troble anyway.
There actually are some Mons in this meta those minimum HP is XX9, those, whose base HP has a four or a nine in the end (74, 79, 84, 89, 94, etc.): Ferrothorn, (Thundurus), Empoleon, Landorus, Golurk and Amoonguss.
From those only Thundurus (now uber), Landorus and Empoleon (UU) may run Life Orbs. Good, that the Smogon analysts put the remaining four EV in something else than HP to keep the Life Orb recoil low. For those who accidently do that, here again: Better don't dump the last for EV into HP.
Coclusion:
1. The optimal number of HP exceeds the sixteenth part by one.
2. Having an odd number of HP allows one to lower 1/4 of one's HP (via sub or super effective Stealth Rocks) more often without dying than having an even number.
3. Life Orb user shouldn't have their HP being a divider of ten - a rule only for Thundurus and Landorus (and Empoleon occasionally).
Special sitiations:
- Having their HP at 338 or higher plus Leftover makes you survive Seismic Toss and Night Shade five times instead of four times.
- 405 is the optimum for those who want to create 101-subs.
- Alls those base 100, who want to create 101-subs, have to use 404.
- If you want to trigger berries or abilities like Torrent and Overgrow should use an even number of HP.
