Assuming it's not ad supported and is just a one time purchase I don't see where your motivation would be in free updates unless it was bringing in enough money

Assuming it's not ad supported and is just a one time purchase I don't see where your motivation would be in free updates unless it was bringing in enough money for you to be living off of. I'd keep track of user requests and things you've learned from the application, if you ever have enough to justify a new game put out a sequel or a new version. Until then I'd feel free to work on a new project.