Being chained to your smartphone means the average worker puts in more than a month and a half of overtime a year, a new study says.Good Technology, a leading provider of secure and managed enterprise mobility for a range of mobile devices, surveyed 1,000 American workers to find that more than 80 percent of people continue working when they have left the office — for an average of seven extra hours each week — almost another full day of work. That's a total of close to 30 hours a month or 365 extra hours every year. They're also using their cell phones to mix work and their personal life in ways never seen before.While 60 percent do it simply to stay organised, almost half feel they have no choice because their customers demand quick replies. Thirty-one percent of respondents admit to continuing to work at home as they find it hard to 'switch off.' Half of Americans can't even put their phone down while in bed, as they read or respond to work e-mails after climbing under the covers.This overtime has become so commonplace that only a quarter of the workers polled said it caused an occasional disagreement with their partner.In what points to changing attitudes to mobile work, well over half surveyed reported no arguments whatsoever from their spouse or significant other over answering e-mail or making work calls at home.The study also revealed:— 68 percent of people check their work e-mails before 8am— The average American first checks their phone around 7:09am— 50 percent check their work e-mail while still in bed— The work day is growing — 40 percent still do work e-mail after 10pm— 69 percent will not go to sleep without checking their work e-mail— 57 percent check work e-mails on family outings— 38 percent routinely check work e-mails while at the dinner table