So, over the past few weeks, I have been gathering info, talking to people and making spreadsheets to figure out some reliable data about plantations.
I've decided to share some here to give everyone an idea on what to expect.
Maybe a lot of this has been figured out by many, but I bet some still are not sure.

Basic info:
Housing: 120 workers/acre
Kitchens: 900 workers/acre
Baths: 300 workers/acre
Recreation: 600 workers/acre
Max workers per 1 acre in Field: 1352
Deaths usually start occurring at 0% health at a rate of 3-5% a day based on working hours.

Estimates Numbers for a 1 million worker 5 star plantation. (These numbers scale so for a 10 mil just do 10x, for 500k 0.5X)
Around 560,000 Bars To 5 star all buildings
Bar Cost 1.12B Gold
Profit: 300-500k/ Day (minus fleets to maintain)
Return of investment 2240-3733 Days (minus fleets to maintain)
With high enough rent or daily deaths, profit is actually in the negative.

5 Star buildings allow crate production increase anywhere from 50% to 100% as you can push over 9 hour work days while still gaining stats.

It seems that with 5-star buildings health finally starts going up instead of slowly down.
Deaths usually start at 0% health, so i suspect that theoretically, workers don't die with 5 stars? Either that or they will take a very long time to die.
With no fleets to bring in workers the return of investment can be as low as 2200 days

More testing needed.

my workers dont die and i dont have 5 stars on anything....
my buildings are all 1 and 2 star with 500 acers and 265000 workers
2200!! oh man

Mack wrote:my workers dont die and i dont have 5 stars on anything....
my buildings are all 1 and 2 star with 500 acers and 265000 workers
2200!! oh man

How long have you had the workers? What's your health like?
Generally, they don't seem to die until health reaches 0% Which can be up to 35 days after getting them on low work.
Health seems to go down daily even with close to 3 stars.

I have found with 3 star buildings, you can just make a little headway in the health and happiness dept. Not all "plants" are the same however. I don't know if each port has a slightly different formula or it's resource related with 7 different formula's. Your population numbers look right but to define the bldg size as a one size fits all, I am a little skeptical

Nice work however on your compilation of observations.
There is a thread on Slack dedicated to port industry to try to figure out the 'rules'' of port industry.

Stan Rogers wrote:I have found with 3 star buildings, you can just make a little headway in the health and happiness dept. Not all "plants" are the same however. I don't know if each port has a slightly different formula or it's resource related with 7 different formula's. Your population numbers look right but to define the bldg size as a one size fits all, I am a little skeptical

Nice work however on your compilation of observations.
There is a thread on Slack dedicated to port industry to try to figure out the 'rules'' of port industry.

Nice good to know. Have you found that your workers actually don't die at all if you're able to bring health up? it's something that I am still wondering if 0% is the only trigger that kills workers.

I agree that different plantations with the same exact setup do not run exactly the same. But it is close enough that it might be within reason "one size fits all" At least with the tests I've done.
But it still needs months of data and billions of gold to know for sure.

Sadly enough no matter what way I look at it Plantations are needed part of the game, otherwise we can't trade but also the slowest return of investment, second place with Goldsmith with about a 2 year full return.

Bigtea47 wrote:

Mack wrote:my workers dont die and i dont have 5 stars on anything....
my buildings are all 1 and 2 star with 500 acers and 265000 workers
2200!! oh man

How long have you had the workers? What's your health like?
Generally, they don't seem to die until health reaches 0% Which can be up to 35 days after getting them on low work.
Health seems to go down daily even with close to 3 stars.

ive had my plant going a few months i can bring in more people, but if i dont upgrade my buildings more my peoples conditions will decline for the size of my buildings im almost in the sweet spot i think

I can't say I have had any of my workers die yet or, at least I have never received a notification if such nor have I noticed appreciable decreases in my worker pops. When I first started plants I only work them perhaps 4 hrs/day but I have been able to increase that to 8 hr days now. With 8 industries to look after, the health/happiness balance has been ..interesting.
I think a good measure of how well a plant is doing is measuring production per acre thus you are measuring the efficiency of your operation.
FTR, all resources are comparable in income regardless of the product produced.
A cotton plantation will roughly earn the same as a tool factory for the same acreage worked.

Stan Rogers wrote:I can't say I have had any of my workers die yet or, at least I have never received a notification if such nor have I noticed appreciable decreases in my worker pops. When I first started plants I only work them perhaps 4 hrs/day but I have been able to increase that to 8 hr days now. With 8 industries to look after, the health/happiness balance has been ..interesting.
I think a good measure of how well a plant is doing is measuring production per acre thus you are measuring the efficiency of your operation.
FTR, all resources are comparable in income regardless of the product produced.
A cotton plantation will roughly earn the same as a tool factory for the same acreage worked.

I track in my sheet crates/acre crates/worker. I find that crates per worker [in field] is probably the most realible way yo get productivity. As atleast for me my acres and works change a lot. Not always being at full capacity.
Are you importing any immigrants? How old are the plantations?
When workers die you dont get any notification they just disapear.
But if your plantations are older then a month and you dont import immigrants. It would confirm that 0% health is the only time they start dieing.

Edit: crated as in units as those transfer across all plantations as you mentioned yourself.

There are no notifications for when your workers die only satisfaction.

CJ mentioned workers will die regardless of their health however, I believe you will get months/years out of a healthy worker otherwise the newly revealed "Skill" level of a worker lends me to think healthy workers are long lived. My workers are all classed as Novice experience and some will be 6 months old. I would hope before they die of old age, they get a little better than a Novice rating.