Wisconsin notice to vacate

[Kat Rathell]

After reading the Wisconsin regulations on serving the 14 or the 28 day notice to vacate on a month-to-month tenancy, I am still confused on the following:

Does the notice have to be served on the day the lease term begins or ends, or does any day work? If it is any day, does the 14 or the 28-day period begin immediately?

Thanks in advance!