I've noticed that salty food has somewhat of an addictive quality; people who eat a lot of it (i.e. fast food or other processed food) tend to bury their meals under a mountain of salt, whereas people such as myself who do a lot of home cooking hardly use (or want) any.
"Season to taste" means pretty much what it sounds like; add however much salt (and other spices)
that you, personally, like the taste of.
If you have a habit of eating a lot of salty foods, then you might want to add a little less than that, for the benefit of people like me who gag at heavily-salted foods.
If you use a lot of other spices, you won't need much salt -
a few shakes of the shaker is enough.
If the food is basically bland aside from the salt (and maybe pepper), then you'll need to use more.
The best thing to do is add a little, then taste, and repeat as many times as it takes to get the flavour you want.
If the food you're seasoning is still raw (and can't be eaten raw), then just put in a small amount the first time you make it and keep track of how much table salt you needed to add.
Just remember, you can always add salt later, but a dish that's too salty is permanently ruined.
cooking.stackexchange.com/users/41/Aaronut
Salting food has a predictable trajectory.
Think of it like a roller-coaster. /\
At first it's not great, then it's great, then it's not great again.
Food with no salt will taste one-dimensional and flat.
The flavors will not "pop".
Add a little salt and the taste of a dish will start to both integrate and become more complex.
With the perfect amount (differs by palette), the dish will just taste great, with all flavors easily identifiable and balanced
(this partly depends on getting other elements of the dish right).
As you oversalt somewhat, the dish will begin to have a sharp but one-dimensional quality, an edge to it.
Some people like this.
It is what many people become addicted to.
As you go beyond this point, the dish begins to taste like, salt.
It has a briny quality that will make your mouth uncomfortable.
As many have mentioned, it's a lot easier to make something more salty than less, so add salt gradually and regularly .
Few beginning cooks know that adding small amounts of salt multiple times enhances the cooking process, allows flavors to meld, and lessens the likelihood of oversalting all at once.
cooking.stackexchange.com/users/1443/Ocaasi
It's a little more complicated to ask how much.
Different people have different palates, depending on what they're used to.
But more importantly salt doesn't just make stuff taste good.
We shouldn't jut sprinkle it on the end of a dish.
Otherwis
the dish just tastes...
Salty Salt affects the water balance in the cells, it can plump up moisture ( brining a turkey- brings in other flavour, and it can remove moisture
( salting sautéed mushrooms extracts more water, creating more browned / flavorful mushrooms.
We really should season as we go.
Salt a little at various stages of your cooking.
Err on the side of caution.
And season at the end- to taste.
The idea is that you shouldn't have add too much salt to get it right.
You'll end up with a much tastier, more complex flavor profile.
And you'll likely use less salt as well.
Unfortunately, there isn't much replacement for experience in this area.
With experience, you know exactly how much salt to use, which type of salt, at which time.
Practice and screw it up a lot.
In the interim, just keep trying General rules though:
Foods served cold need more salt.
A properly seasoned hot dish will be under seasoned when cold Starches absorb salt - potato salad needs to be salty, the next day it will be less salty Or potatoes in a stew will suck out the salt, you'll need to reseason
For these reasons, chefs always season their mise en place, then when finishing the dish, alwfays check the seasoning.
cooking.stackexchange.com/users/4179/Chef
I would say it depends.
Some recipes need salt to work.
If you use yeast, you need salt to control the gross.
If the usage of salt is for taste, I first look if I can use a healthier substitute.
This depends on the particular dish, however, since in my family we all like hot spicy food, we usually do not need any salt.
Instead we enjoy the healthy benefits of turmeric, ginger and other spices that even make the food tastier than with salt.
cooking.stackexchange.com/users/62/txwikinger
Salt to taste means exactly that.
You add a bit, taste it and then repeat the process until you like the result.
Of course that once you've done the process a lot on different dishes, you will have a feeling for how much to use and you'll have to repeat the process less or even skip it completely, but what's the fun of cooking without tasting.
For things you cannot taste and repeat (like when cooking meat on a grill) my taste is to add a pinch on each side of the meat, evenly distributed.
No way to tell what's yours so... Rule of thumb: It's best to err on the side of missing salt than the other way around, so be shy.
At worst you'll have to use salt on the table to fix it, but it'll be edible.
cooking.stackexchange.com/users/89/Vinko Vrsalovic
Salt to taste.
As others have written.
Add a pinch of salt.
Stir.
Wait.
Taste.
Repeat.
I use very little salt for myself, so my rule of thumb is that when I start tasting it's salty , I'm done.
My wife need far more salt than that.
cooking.stackexchange.com/users/641/BaffledCook
I find it hard to figure out how much salt to add to dishes. I'm always afraid I'll make it too salty. Recipes always call for salt to taste, but what does that mean?  Is there a good rule of thumb?
How much salt should I add to a dish?
cooking.stackexchange.com
<flavor><salt><spices>
cooking.stackexchange.com/questions/556
cooking.stackexchange.com/users/183/papin
There is a wide range of personal preference here, but when cooking it is better to add a little at a time throughout the cooking process to avoid over salting and allow the flavours to blend. When using a lot of other spices, less salt is usually necessary. It is better to be cautious and add a little salt but do it several times, then adding lots of salt at the end. It really depends on your taste. 
The more salt you eat the more you need. You should only add a little at a time. It is better to salt a little but do it several times during cooking. It depends on your palate. If you use other spices then use less salt. You will need to develop your own experience.