@AC
Sorry - wrong on both counts. System and software designer/developer with a number of years of experience under the belt. PhD in Fault-Tolerant and Real-Time systems, worked on kernel device drivers for the Telco division of Sun Microsystems, did the dot-com-bubble thing as System Architect for a B2B marketplace service provider, worked as a consultant software engineer/designer in the distributed systems (CORBA, J2EE) market and ended up doing various technical design and oversight things on large-scale contracts, such as the wonderful (NOT!) NHS care records system and various other major government and corporate IT outsourcing deals.
And, you know what? By the simple expedient of having properly trained (and intelligent) staff members, clearly defined reporting/escalation structures and a reasonable amount of advance planning, I have managed to avoid the situation of having to access systems, check email, etc. on my phone. Wow! How's about that?
On those occasions where something went sufficiently wrong that I needed to be contacted urgently, a simple phone call usually sufficed and I could ensure that someone would be able to deal with the problem. Or at least contain it long enough for me to get decent network access at home, at an office or via WiFi/VPN from my laptop in the hotel/station/airport/wherever.
Believe me, if you think that you, or the things that you do, are _soooo_ desperately important that you simply must have 24/7 access to your email (or whatever) via your phone, you will ultimately feel severely short-changed when your employer or client decides to save a few bucks and outsources your job to someone else who doesn't do the 24/7 thing on their own, but does employ a few guys in India (or wherever) to monitor stuff for them.
(Like all generalisations, I can think of possible exceptions to this. Although the only one that springs immediately to mind would be C&C support for the emergency services. And those should have properly manned data/control centres 24/7, so there should be no real need for some critical bod or other to be checking on email or systems via their mobile.)
In my experience, people who think that they simply _must_ have 24/7 access to their systems or email like that are either spending too little on their service providers (or on employing additional staff) or are over-estimating their own importance...
Of course, YMMV. That's just my experience from what I've seen in the various places I've worked.