If the free version works for you, well, there ya go.
But if an app is something that really helps you, you like it, and you use it a lot, please reconsider a paid subscription - for whichever app you like the most.
Behind a great piece of software is a crew of of hard working people that took a great idea a *very long way* to finally reach your phone.
While dozens of other companies failed, they worked hard, listened to the users, worked even harder, and survived.
They should get paid for that. And as the beneficiaries of all that effort, we should be glad to pay a reasonable fee.
My Strava subscription costs the same as me buying just one of those folks one beer in a bar once a month. Seems fair to me.
Free apps are for free-riders. Just decide what's right for you.