For the first ~20 years of my career I had a job where someone was always there doing my job for me if I wasn’t there. I work for a very large chemical company in a 24-7 facility.
Last year in January I took another job managing projects. I was issued a work phone and suddenly for the first time I had to get my work done even if I’m not there. I voluntarily have email on my phone and I don’t mind replying after hours but fortunately those are few and far between. I really don’t feel tethered to my job yet and most of the off hours email can be dealt with later.
The last job I was at required 12 hour shifts and you could not leave. Talk about tethered !