I'd be lying if I said "no". My clients were all plaintiffs' firms, and sometimes paying me wasn't a top priority. But after a while, I learned the best times to invoice. Such as, not within a month before the end of a quarter.
Edit: That being when partners got their distributions.
Do you think you would benefit from having a low fee/interest line of credit available where you could get funds if necessary when clients don’t pay/pay late?