repairing leaky windows

We had a contractor in to look at our wooden casement windows (and some other things) a few months ago as we were considering replacing them due to some minor water leakage. He told us that all we had to do was replace a few inexpensive parts, do some caulking, and they would last us a great deal longer. I want to do some research on what needs to be done so I can decide if it's something we can do ourselves but I can't remember what the parts were called, aside from the weatherstripping. It had nothing to do with the crank... What could possibly be replaced by a novice on these windows that would help prevent leakage? Please help!

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