Answered by Robin Howard in Episode 1;
Wedding Hair and Makeup takes about 30-45 minutes added onto how long it usually takes you to get your hair and makeup done because of the conversations, drinks, and jokes that will happen during getting ready.
If your friend has long amazing hair or anything else that would take extra time make sure to add on timing for that!
We usually suggest adding an hour just incase, worst case you use the extra time for drinking and talking :)