You will come to dislike the time it takes to zero the modules. No matter how efficient/fast you get it to zero, it will seem like an eternity especially during auton. The next step you’ll take is to pre-position the wheels for auton which is what we did but now there is the human error factor. Lets say that you accept this, you will zero the wheels after auton which means other robots will have moved somewhere between 2-3 ft before you start moving. The best bet is to go 1:1 on the azimuth and use the absolute built into the VEX encoder or hang an absolute on the module as others have.
As far as things moving over time, the same can be said about the magnet and/or the sensor used for zeroing.
If you can figure a way to do it without a zeroing switch, you will be happier, guaranteed.