Speaking as a contractor, I have a bias/tendency to eventually "fire" any client that takes too long or is too sketchy about paying me. Too much risk on my part. I work, I get paid. With all bullshit set aside, it should only take on OOM of about 1 minute to write a check, put in envelope, put stamp on it, and put in outbound mailbox. Anything longer than that is self-imposed bureaucracy, not physics.