Does your manager expect you to be reachable when you’re not clocked in?

Are you expected to respond to calls or texts on off days or even an hour before your shift starts (not clocked in) for instructions on what to do for the day or for emergencies? I usually don’t answer phone calls or texts UNTIL I’m clocked in to keep that work-life balance and to build boundaries for coworkers and managers to not reach me outside of my work hours. But some argue that during work emergencies, you should be able to be reachable. What are your thoughts and do you adhere to it?