Question: Why do we need to worry about change? Shouldnt it be enough to send the exact amounts plus fees? Thats what I do with all my transactions at least.
You do it with Bitcoin transactions or are you referring to another currency?
If you have 1 BTC at an address and you need to spend 0.2 BTC, imagine that your 1 BTC is in the form of a paper bill. You need to spend the entire bill/1 BTC because you only have that one bill and no smaller bills. 0.2 BTC is going to the destination address and the rest (- the fees) is the change in the form of a new paper bill, worth 0.8 BTC that is now going to a new address/another one of your pockets.