What's routine mean? I've had people that go all Peter Potomus and start beating down the office door if you don't reply to their insane, rambling emails inside of five minutes, screeching "Did you get that THING I sent YA!"
Email is a medium that should require a little bit of thought and deliberation, and if you're doing it, you can't do much else. Incoming-email-driven development is one of the more frustrating and wasteful processes I've suffered through. Ping ping ping, bouncing all around, not concentrating.
It's also worth trying to cultivate some self-reliance in your coworkers, so they learn how to find information and solve problems on their own, without needing their hand held every step. It's sometimes overwhelmingly difficult not to send back a lmgtfy link to some questions.
If they're routinely dropping emails then they haven't communicated up and down that they're overloaded or they're in a shitty work environment. Either way, I've been on the other side of dropped emails and it's like sand in a motor. It's precisely why most large organizations have issues being agile.
