I find it is rare that my guests completely finish the wine that is in their glasses, before dinner. I don't want them to gulp! I like it when they bring their unfinished glasses over to the table. It allows the evening to flow from the appetizers into the dinner.
So, I set my table with one wine glass for each person. If someone would like wine with their appetizers (some do not), I will use their glass from the table. The rest are left on the table for those who choose not to have it with their appetizers but may have some with dinner.
If, during dinner, someone wants to switch wines, I will take away their old glass and replace it with a fresh one.
"Education is the most powerful weapon which you can use to change the world." Nelson Mandela