If you are planning on making an app or service with the intent of making money you definitely need a solid business plan, and that includes scouting competition. If you think you can expand on a feature or better a current app go for it. If you look at most apps reviews you can gather ideas for features, etc. People want simplicity, customization, and overall they want something to just work without spending too much time learning about it. I would say a high percentage of apps on Google play are crap, and a very small percentage listen to the users.
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