We are building a mobile app that does not use any long press interactions in its UI. However, we observed some users tapping longer than expected when trying to open the menu. As they tapped too long for the event to be triggered the menu didn’t open. Is there a usability standard for this?
There are some OS based standards for this. For example, iOS has 3D touch for hard touches and you can rearrange your home screen after a long tap. When you hold your tap in navigation the touch event will be triggered on release.
However, there might be something bigger happening here. Why are your users having a long tap?
The best thing to do here is figure out why users hold the tap longer than you were expecting. Maybe your users are insecure about what to expect after the tap. It's better to fix the deep issue here than to put a patch on it by fitting it into a usability standard.