Sweating the days away.  I remember when I first found out about 'toggle auto-use tool' under the action menu (press 'y' default key), then 'control' tab along bottom of action panel, then the '>>' in the middle of the bottom of the action panel, then over three times '>>'.  then there on the lower right is the 'toggle auto-use tool' icon/button.  Setup a keymap to get this icon mapped to (I prefer) a number key such as '0'.
Then when wanting to continously use a tool, equip the tool, press the '0' and away it goes, no clicking.  Aim the tool and go clickless (click to aim) I should say. 
If I had known about auto-use years ago, not 4 years in, my life would be a lot less clicky.  I logged some 300,000 some clicks sweating before wising up to 'toggle auto-use tool'.  Clicks not wasted as I still have A LOT of the sweat looking for better prices in better neighborhoods.  And I have sold about as much as I have left.  (takes some entropia math to understand that, 1/2 of 1 is 1/2, start with 200,000 sweat, sell 100,000, have 100,000 left) 
Now one of the complaints I've seen about 'toggle auto-use tool' is that auto-use makes avatars look like they are controlled by bots.  Botting, being a automated way to play other mmos and usually against those other mmo's rules.  But in entropia 'toggle auto-use tool' is a boon, a clear plus, and saves much sanity from fleeing mice and keypads.  And auto-use is within the rules of entropia as 'toggle auto-use tool' is included in the action panel list. 
The inclusion of auto-use goes a long way towards making entropia gaming A LOT more fun and less demanding.  There are a few problems still as it applies to sweating but on the whole 'toggle auto-use tool' is a keymap tool to use that I cannot live without.  Hope you have found auto-use and good luck.

Sweating is about connecting the beginner entropians with the experienced entropians.  A sort of one feeds the other and everybody's happy in the end.  A mutual agreement to produce and buy/sell from each other.
As sweaters collect their sweat and turn it into welding wire or mind essence, the free-to-players produce something for the space and vehicle owners/operators.  Still low-cost for either.  The difference is measured in $100's of dollars, sometimes $1000's but really the amounts connecting are low. 
A low-end stock for comparison might sell $100,000 in a day in a few seconds, no problem.  In entropia moving that amount would have a huge effect on whichever market it was in.  In stocks, a 5-10% blip of $1,000,000 or more is in a typical day (minute) and does not have much effect. (need a chart and trade records to show this, an IBM ticker symbol on a finance site and some sample trades)
Sweaters collectively, however, can approach I would guess $200-$500 a day (24 hours).  That's the pool of demand available.  It varies but generally within $100 up or down in market volume.  Split that by who knows how many sweaters to arrive at a typical sweaters' experience.  I would guess some 200 sweaters in a day.  Large enough however to fuel a lot of play.
Keeping in mind the $1 per hour cut, sweating can still be profitable as outlined in an earlier post.
As the spaceship owner/operators need welding wire the sweaters will be there to provide it even at breakeven or a loss as 'it's just a game', 'sweating is free', and 'sweating builds skills'.  The three reasons most cited, particularly skills, give the new player an opportunity to connect with the spaceship owner/operators who are buying and selling goods between planets.  Also to mainly build their own avatar's skills.  The sweat sold contributes to keeping the spaceship people with operating spaceships. 
Sweaters are connected to the in-game economy in important and satisfying ways as other professions are connected to sweaters in satisfying and important ways.  Join the sweaters.  Join entropia universe.

sidenote:  annualizing the average sweat demand over a year is $127,750 of sweating per year. and by 200 sweaters about $1-$2.50 per sweater per day.

Population estimates after some more crafting, more basic sheet metal, and a server change from being on too long, then being logged out.  what happened?  I don't know.  I wondered if the population numbers would change?  from searching the player register i got an average of 3-10 players or 6.5 players per page.  For 30 pages times a maximum permutation of 15 results a page, a 1.4% active players per three letter permutation.  Those are players who are online at any given moment. 
There are some 17500+ three letter permutations when searching the player register.   Of those 1.4% will be active.  450 players per search. and 1.4% of that is:   6.5 players. then multiply that by 17500 permutations of three letter search terms for ta-da-da-da: 113,400 players active at any one time.  My sample size is small.  Less than 20 but more than 10 searches.  So the confidence level is likely around +/- 20,000 players.  Just a guess.  This is but one of many ways to gauge the active population on entropia, particularly Calypso.  With such a population and active auctions and private trade, Calypso's peds flow greatly day after day, week after week, pull after pull.  Be part of and enjoy your time on Calypso.

Playing entropia on calypso, again.  I turn on my computer.  Among the first things I pull up is the client.  without thinking I am nearly seamlessly in the world.  Check some auction prices and market activity.  Then after a few purchases and recording of sales, I craft.  For hours.  It's awesome.  The amounts of money that flow in the virtual landscape still amaze me.  And the money does flow to my bottom line with a lot of dips and highs along the way.  Past a certain level it is possible to have the downswings mean less as they are quickly recovered within a day or two.  Across the three (four sic sweating) professions; hunting, mining and crafting.  Favorable buyers and a good reputation are also some keys.  Be ye not afraid.  There is enough activity for all.

The wonder that is the entropia universe.  The planet beckons and calls.  An irresistable urge to play and be played.  How much?  How much time? Endless.  An entertainment like no other.  Always something to do.  A productive player is a happy player.  Efficiency matters.  From the splash screen of the game load from the client.  The ships displayed and the planet are all explorable by an avatar.  The scope is breath-taking.  The actual play creates hard-core players by the thousands.  I am an entropian colonist, a settler, and a crafter.  Join entropia, they say.  Do some sweating, they say.  Become a pioneer in this new world.  And find yourself as well as others who share in the destiny of the online worlds.

After sweating for a year on calypso I collected some 140,000 sweat.  that's 3 hours per day for 4-5 days a week off and on over a year.  More concentrated effort would have yielded more but then i wouldn't have time to write blog posts or live like a pauper.  anyway i have a huge amount of sweat left that i slowly convert into mind essence and welding wire.  The effects of all the time spent I offset with healing and hunting and scanning.  Paying the piper so I can dance to the tune. 
Is this a success story?  Not yet, but I feel the story is on the way.  Perhaps others could succeed faster, better, and more by reading the few bits of knowledge in these posts.  Drop a comment and I'll see what I can do for you and the wonderful world that is Calypso.

have been playing entropia on planet calypso at a different level now for a week.  really stepped up my spend and sold figures from $80 working capital to $300 working capital.  cycled roughly twice per day.  which when i think about it is amazing for some data on a server visually represented then enjoyed by 10's of 1000's of people. 
remains to be seen how succesful i can be as my play style with crafting is hands off for the most part.  though other professions may involve doing more on one screen i find that crafting is perfect for multitasking.  attended to when needed but largely hands free.  i still do superstitious clicks and mouse moves to make the majic of crafting gods turn my way.