There are a lot of debate on whether maps are a hindrance or a benefit to your story. I think that like any other writing tool or technique that a writer can use, it should be considered carefully for each story, thought out thoroughly and done on a case by case basis. Not every story will warrant a map.
The first important question to consider is: will it add to the story for the reader? Do you think that there may be too many names floating about in your prose or do you feel that the layout of your places are pretty straightforward for the reader to follow? When I read George R.R. Martin’s A Song of Ice and Fire, I had to often look at the maps to keep the story straight in my head. For that matter, he had so many characters going all over the place and working with so many different characters, I even made an Excel Spreadsheet to keep the names straight! But Mr. Martin has such a great talent and incredible story that I forgave him as a reader and put in the extra effort.
Another question: Do you feel that the map is going to help you as the writer? Will it guide you in keeping all the facts straight and keeping an accurate idea of where each character might be? Or will a map also give you inspiration or show you where you have room to grow?
When you do decide, you will also face the dilemma of where are you going to get it? Are you going to draw it yourself and if so, do you have the right amount of cartography skill? If you are not taking up the challenge to create it, then what resources do you have to get one? There are a ton of “free map images” out on the net, but then you may have to make concessions or even possibly alterations to your story. Perhaps you might be wise to invest on getting it professional completed. There are also many websites that will provide map-making services or websites like Cartographers Guild that has a forum for questions and/or advice.
Overall, the questions surrounding the “to map or not to map” debate really comes down to time, resources and whether or not it will benefit you as a writer and/or the readers.
For myself, I have started my sequel and I think it will be a positive addition for the readers to see where the lands are and maybe help give the readers a better perspective of all the key lands that are involved in the story. My plan is to make a map of both worlds detailed in the books. And yes, I do plan on designing the maps myself. I designed several in my old Dungeon & Dragon days and found that it really provoked ideas and plots (usually evil plots to mess with the players!! haha)
I will keep you all in the loop and hopefully share my maps soon!!