I have seen drying up cows one of two main ways.
One way is to dry them up 2 months prior to calving and using tomorrow.
The other way is to "wean" them off milk by milking them once a day for a few days, then once every other day then dry treat and sometimes, they will only use orbeseal and no tomorrow.

Which method is best? Weaning them off milk can maybe allow you to milk the cow longer without harming calf development, therefore more milk/money, but the cow can see a small rise in scc. Skipping the cow also means making and keeping a schedule for when she gets milked and when she gets skipped.
Which one is more economical and better for herd health.