Home stwiches do you use them and why or why not? Would they be handy for changing bits?
I don’t use them. Back when I was suffering through frequent freezes, I bought the switches and the cabling to connect them, thinking that they would allow me to re-start the project from the same machine zero position. Then, I seemed to have solved the freezing issue and never did get around to installing the switches. As for the “why not”, I guess it’s simply because, for the type of projects that I do, I don’t see the benefit. I can re-zero the Mill to the starting point without using them.
As for your question about changing bits, I do that for almost all my projects. When the first toolpath in a project ends, the Mill returns to X0Y0. I remove the first bit, put in the second, reset Z0 and run the next toolpath. I see no advantage to having switches in this scenario. In fact, you run the risk of having your X and Y being off a bit owing to all the moving of the gantries.
I expect that those who have installed switches will be able to explain the benefits of having them. Then, you will have both opinions and be in a good place to decide if you want them.
I use them because I have several “permanent” fixtures on my table. I also established a tool changing position (grbl does not perform tool changes). I agree with gwiki and not going home after every cut. I also do dumb stuff once in a while and run 10" when I meant 1" and the switches prevent even more silly stuff from happening. I have four machines and only two of them have limit switches.