First, take a good long look at your boat and note any place a line could rub. When lines rub anything (even each other), chafe is a possibility, maybe even a probability. Make a list. Where do dock lines touch anything? For example, chocks, over the edge of the dock, or around a piling. And don't just look for places lines touch while you're at the dock. What about when you're at anchor? And what about attached to a mooring ball?
Now that you have a list of all the places lines could potentially rub and chafe, you'll need to know what size line is in each place. And also, what size the fitting is that it will be going through, if any—chocks are a prime example. Once you know the line size and size of chock, then begin looking around for chafe gear.