I have a couple fairly simple Android apps on Google Play. I've gotten a few reviews which somewhat surprised me (though they probably shouldn't have) asking about adding an option to use a light theme, or an option to set font size.
Font size seems like something that shouldn't be adjusted per app in general, since there's a global setting for font size which should provide a reasonable setting for all apps. Light vs. dark theme seems more reasonable; perhaps Android should have an option for users to specify their preference, but that's not available in standard Android as far as I'm aware.
Perhaps it would be best to just implement both these things since they're easy enough (though implementing every feature that someone might like would lead to rather bloated apps). But what would be considered the best practice? Is there any other customization of style that a typical app should offer?