There is an application named unity remote , you can find it on google store . It permits you to run your game in the unity editor and use the tablet to control the input.
A small heads up on getting it working , you need to enble usb debugging on your tablet , it needs to be plugged in at the time your open the unity application. IF unity was running first and you plug your tablet in afterwards it doesnt seem to work.
If you are testing changes in input/game controls, then using UnityRemote is sufficient (it’ basically does screen capturing of the Playwindow and redirects input from the device to the editor).
If you are just testing some scripts/changes, it is often possible to test it in the editor, if your can be controlled without a touchscreen.
If you test performance or new graphics (i.e. you added a new shaders and want to see if it works on android) or some Java Plugin, then you must build and publish it every time