Hello, I've been wondering for awhile if there is any benefit to having both Min and Max endstops on all 3 axises of a Prusa i3 style printer? For example, can Marlin be configured to automatically determine print volume based on them?

From a practical point of view, three endstops (i.e. one endstop for each of the X, Y and Z axis) is both the minimum and the adequate number of endstops for a Prusa i3.

Marlin can make use of both min and max endstops but most people just use min endstops and configure the max value for each axis in the Marlin Configuration.h file.

Let's say, I put all min and max for each, after resetting the printer from power disconnection/off, will marlin register it as max when hitting the max or will it simply just crash and force its way there? I don't know if it's true, ramps 1.4 max endstop ports somewhat unused or something so putting max also a useless thing to do

If you have properly adjusted min and max endstops and have configured Marlin properly to recognize all of them, there is simply no way to get a print head or heated bed crash.

But you can also avoid any head or heated bed crash by using only min endstops and properly configuring Marlin, and properly homing the printer after each power on or reset. This is why I wrote above that only three min endstops are required and sufficient for a Prusa i3.

Because sometimes I forgot to home the axis first, happened to me once, then I raised the z to 150mm without homing, it crashed to the top bracket, so I still wondering about this