Mobile apps niche analysis (App Store & Play Market)

I've noticed that quite a lot of mobile apps launched here at PH are most of all just one more try to blow up the niche. Is it the right flow to start? 1. Do you usually do niche analysis before building a new mobile app? 2. What tools do you use for that? Is it one tool or a bunch of services? 3. Are you making it on your own or with the help of a product manager/analyst? Very interesting to hear one's thoughts on those who are launching their apps, and spending time & money on that. How do you find the answer "If it is worth it?"