Normally one shouldn’t have to wonder if the person beside them, carrying out the same job, is getting paid the same. But curiosity killed the cat as they say, and we have all been there before. You look at another actor with similar amount of text as you and question if he’s getting the same amount of money. Or another writer on the same show as you, or a director…whatever the case. The answer is most likely: NO. Lets take the first as an example: Salaries for actors have a set minimum if the project is unionized, and you will never be taken advantage of being paid less than established, but once the minimum is set, there is no bar or law that establishes equality among cast. So he or she may be earning more than you. It mainly depends on two things: Experience and representation. Experience is more about your popularity among the industry or, in special cases, the lack of other capable of carrying out the job. If you have been in very popular shows, and your face or name is one the audience knows, then the more likely they will want you as opposed to an "Unknown". 
Representation all depends on how well your agent can negotiate your contract. Generally it is something we cant or don’t play a part in, but simply must trust our agent does his or her best on. After all, the more money they get us, the more money they get themselves. If they can sell you well, and know when to take a risk asking for more pay, then the more likely you will get a higher paycheck. The one mistake we can make is to ask others on the job how much they get paid. It is more likely to cause problems (for you, your agent, theirs, the producers or anyone else) than it is to satisfy our curiosity. If you want to know about the average paycheck, and you feel it is not (Pay attention this is crucial), I repeat NOT inappropriate because the relationship is not strictly proffesional, then you may ask how.. much they get paid for IN OTHER PROJECTS that have nothing to do with you or are in strict competiction with you. Sometimes an innocent question can lead to a lot of problems and even lawsuits that you might not want to get involved in. For example you shouldnt ever ask another Action Movie director how much they get if you are also an Action Movie director! Find out on IMDb or ask your agent. But never ask someone about their salary directly, or even worse, ask and then go to the producers complaining because they earn more. A simple rule needs to be followed: Dont Ask, Dont Tell.
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