I work the helpdesk at a fairly large company, and so far have been quite successful at keeping working and non-working time separate. I do have to do 7 days of 24 hour oncall every 8 weeks though, and it's murder.
My normal shift is 4pm-1am. Oncall starts as soon as I clock out, and I'm usually getting calls on the drive home, thank Bob for automated voicemail to text transcoding.
Typically there is a stretch from 2am to 5am where there's no calls, and the day shift doesn't get on the lines till 7am. So I sometimes manage to sleep an hour or two between getting off work and getting "morning" calls.
Can't complain though. I'm not salaried, and have hourly pay, so I don't consider my time "owned by the company", except for when I'm oncall. and deliberately choose to be totally cutoff from work during non-work hours. I can imagine checking email and taking calls after hours. It's unsavory to say the least.
Whatever happened to that old union slogan: 8 hours for work, 8 hours for myself, 8 hours for sleep?