Jobs

In the world of Fairy Tail there is an organized system of jobs a mage can take, these jobs all vary in difficulty and are divided into different ranks. Basically there are 5 job categories in the world of magic.
 * Normal jobs- these jobs are the easiest in difficulty and a mage does not need to be exceptionally strong to undertake these assignments. Also the pay can be rather moderate.Gildarts_actual_appearance.jpg
 * S-Class- these missions are extremely dangerous(as commented on by Mirajane), in order to undertake a S-Class job the mage must be S-Class. An exception to this rule is that a group of non S-Class mages are accompanied by an official S-Class. The reward for these jobs can be rather large, spanning in millions of jewels.
 * SS-Class- These missions are more dangerous than S-Class mages, it can be inferred that only S-Class mages can undertake these missions due to the sheer danger. The reward for these missions are most likely greater than that of the S-Class missions. Gildarts Clive of the Fairy Tail Guild is the only known mage to undertake such a job, the fact that he is the only one in Fairy Tail(a man whose power is second only to Makarov) who can take them it is obvious these missions are extremely risky.
 * 10 year- these are above SS-Class in risk and difficulty, they are called 10 year jobs simply because these missions have been up for grabs for 10 or more years but no mage has completed them. These jobs are incredibly dangerous in nature and most likely have a very promising reward for completing them.
 * 100 year- These are the highest class of jobs in the world of magic, these jobs are so dangerous that in 100 years no mage has been able to complete them. Only mages of the highest caliber can handle such a job, Gildarts Clive being a person to undergo a 100 year mission and survive. It must be noted that on Gildartz's mission, he was the first one to come back alive as commented on by Makarov, this alone is a testament to how frighteningly dangerous these jobs truly are.