I have homing switches on my CNC and I use them when I change bits.
I usually locate the work piece close to the center of the CNC. I do this by homing the CNC and then precisely jogging to a location which I use to fix the work piece down. Once that is done, any bit I put in will find the same location once I home and jog by the same amount. The only thing I have to watch out for is the Z height.
Since I don’t have a touch plate, I use the paper method and I keep a spot on the work piece un-machined so that the bits can all start from the same height.
This system is also useful when you break a bit. The new bit goes in, you home and the jog, you set the Z and the new bit will follow where the old bit cut. Usually I edit out some of the G-code to skip what was already milled.