I'm considering making some features I need for Polar required unless you pay for premium but they're privacy oriented so I'm a little worried about user backlash.
For example, when you save a web page offline, I want to ask the user if it worked on a scale of 0-10 and then save the URL anonymously in our telemetry system along with the rating.
What I was doing was making the first say 50 NOT require this but make it optional.. and after that it's required.
If they want the option to bypass they can go premium for 4.99 per month.
I'm also thinking of giving them the ability to turn off analytics for the same price. $4.99 and they aren't tracked by GA.
I rely on that data to build the product and by not using it they're not "paying" so allowing them to opt out for $4.99 seems fair.