When does it become more polite not to respond? I got a few emails a few months ago, during a time when I was just totally and completely swamped and had pretty much stopped dealing with email at all. Some are from acquaintances who wanted to get together (in vague "We should do something sometime!" sort of ways).
→[More:]I'm still busy enough that I don't really have the desire to make time for these people; I barely have time to see the people in my life who I really like. But I feel bad that I never responded to their emails. But responding would compel me to schedule something.
Best practices?