This isn’t something that should really be set by users of an app. It should be set by you, as you will be the one to handle user feedback and bug reports.
That being said, bigger releases are a challenge from a debugging report standpoint because you are introducing many more changes in each release compared to a smaller number of charges in more frequent releases. This is why many devops teams in corporate land try to keep releases smaller and more frequent (see also: Agile Development)
Just don’t try to run huge amounts of bandwidth or try to pirate content on it and you’ll be fine. It does need a credit card on file, but it cannot charge it unless you explicity disable free tier.