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Depends what app etc. Today almost everything is lifetime - until developer decides not to support it anymore and do updates. What guarantees that app isn't abandoned after 1 year

At the moment I would probably not do any IOS app that was subscription -
 
I'd rather pay the on-going subscription or consider other options. You can always feel differently about an app one or two years down the line and it's a lot harder to stick to the last usable version these days.
 
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