3182 - Our custom is to immediately affix all the mezuzahs upon entering the house without a beracha

After thirty days, you take one off for inspection and replace it with a more beautiful mezuzah. The new mezuzah is affixed with a blessing, and you keep in mind the other mezuzot with the blessing. https://www.torahrecordings.com/rebbe/igroskodesh/010/004/3182