In today's wonderful world of cuisine, salt has evolved from being just another staple to a myriad of choices based on texture, flavour, and health, from sea salt to exotics such as "fleur de sel" or Himalayan pink salt.
Regular table salt has taken quite a beating lately. More recipes now ask "sea" or "kosher" salt, instead of simple "salt," because the larger crystallized shapes offer slight flavour attributes over table salt - and because sea or kosher salts do not have the additives of regular table salt has, and thus offer an arguably cleaner taste.
That said, note that all salt is sodium chloride. The ingredient list on a box of table salt from my pantry includes salt, calcium silicate, potassium iodide, and sodium thiosulphate - that's three additives.
A document from Sifto Salt Corporation shows production averages in the year 2007 put the additives at less than one third of a per cent. Why are they even there?
Calcium silicate is an anti-caking ingredient to keep the salt free-flowing instead of clumping.
Potassium iodide is a source of stable iodine, an important chemical needed by the body to make thyroid hormones, added to salt to help protect against Iodine Deficiency Disorders.
Sodium thiosulphate, from what I can find out, is added in very small quantities to help prevent the oxidization of the iodine.
Everyone has opinions, just as they do taste buds, and my preference is to use and recommend good old table salt, when it comes to cooking where the salt is going to be dissolved in moisture with a number of other flavourings and ingredients. Raw applications, however, or finishing procedures, benefit from gourmet salts, such as varieties of sea salts and kosher salt. Such applications include raw vegetables, salads, and any recipe which requires a finishing salt to be sprinkled on the finished dish. It allows the consumer of the meal to taste and feel the differences that these gourmet salts have to offer.
My advice is to help you save money and make sure you have enough iodine in your diet. Use table salt for everyday cooking, except when a finishing salt is needed. When gourmet salts are dissolved in cooking, the characteristics that you are paying for tend to become nonexistent, and table salt is a fraction of the price.