1. only expires after the garnishment is paid (instead of after 6 months like prior garnishments would have);
2. creditors have to pay $35 to each garnishee; and
3. wage garnishments must be served in accordance with Michigan Court Rules.
This means, once you have a judgment in your client's favor, and 21 days have passed (during which the Defendant hasn't filed an appeal of that judgment), you will need to prepare a Request for Garnishment, (use the SCAO form, that's easiest) file it in court, serve it on the defendant, and mail to the garnishee (employer, IRS, whoever is paying that defendant).
A defendant will have the chance to object to garnishment, as long as the defendant does so within 14 days after being served with the Writ.
For more information go to the Michigan Court Rules. Look specifically at MCR 3.100 et seq.
(snore snore! I know, right?)