I have a client with 18% of his receivables past 90 days. Very sloppy.
Having said all of that, the difference is we actually pursue all of that debt, rather than letting it sit until someone decides to pay us (although you end up waiting anyway, LOL).
Some of my work is as a technical expert in IP litigation. I was sitting for a deposition on one, and part of the taking attorney's job is to try to establish that I have a bias in favor of a client because they are paying me.
Attorney: "What fraction of your annual income is coming from this case?"
Me: "I don't know."
Attorney: "You don't know? Approximately how much have you been paid so far?"
Me: "I don't really have a way of answering that."
Attorney: "Why not?"
Me: "I'm not very good at submitting invoices; it's probably been four or five months."
Attorney: "You should stay on top of that.
Always submit your invoices every month."
In my defense, the consulting income is "extra" because it is unpredictable, and we don't budget for it. But when even the opposing counsel was advising me to shape up, I figured it was time to shape up.
I'm typically much more prompt these days.
(We managed to banter about the Michigan/Ohio State rivalry on the record as well--he was from OSU. But that's another story for another time.)