There is a fine line between communicating to clients and prospects that we care deeply about their projects and being an angst-ridden pest. But, to get and keep clients we better master discerning that line.
Admittedly it takes a while to make the paradigm shift from being an invisible presence (as vendors once had to be) to a partner. Initially I stumbled badly. One prospect banned my compulsive emails. At the time, no, I didn't realize that such constituted over-communication and was a sign of insecurity.
Now, I got into the rthymn of knowing how and when to connect back with clients and prospects. Their appreciation is palpable. That happens, even when they are officially on vacation. Today I took that risk of relaying my concerns about the hiatus in the project. Those in the loop, including the person on holiday, were pleased that I was presenting myself as a kind of partner, not just a paid vendor.