I really wish I could do this 100%. I leave it off most of the time, but I have to be on-call for my day job every few weeks and can't really not have a phone

I really wish I could do this 100%. I leave it off most of the time, but I have to be on-call for my day job every few weeks and can't really not have a phone then and still keep my job. It's a shame that phones are so closed and proprietary. I looked into changing a phone's IMEI number, and turns out that's illegal in most places and a serious no-no. How can there even be a law like that??