You can have multiple transactions sent to and from one address. Bitcoin addresses are only really used when receiving bitcoin.
Bitcoin has used different standards over the years leaving a few standards in use at the same time making the complex string of character even more intimidating than it needs to be.
Bitcoin address used once. A higher fee will encourage miners to give your transaction. Your landlord can see your salary when he raises the rent he knows exactly how much to ask for. You use a single bitcoin address for all your earning and spending.
Unlike our real world addresses they are only meant to be used once. Anyone you trade with can see a complete history of your finances. Once an address is entered simply say how much you wish to send and a fee you are willing to pay.
Your bitcoin wallet can have as many addresses as you want and you do not have to change addresses every time you make a transaction. Although you can use the same address more than once it is not recommended for the sake of security and maintaining anonymity. The idea is that for each bitcoin transaction receivers will.