HRMS - Payroll for North America: How often do you do maintenance?

We are running HRMS and Payroll for North America.  There are 6 tax updates per year.  According to document 1100013.1, bundles come out every 4 to 8 weeks.  This would mean that between tax updates and bundles, I would be  applying maintenance between 12 and 18 times per year.  Is this normal?  I am interested in finding out how other shops handle maintenance.

Thanks.