Unless you've created a huge bar area in your home and are passionate about crafting different cocktails or impressing your guests with the right glass for any drink, be realistic!
Consider your drinking habits, household size, regular guests and storage space:
Everyday glassware sets usually include between 4 and 16 glasses. Because you can use them for more than one drink at the time (e.g. water and juice), you should have more than one per person and a few spare glasses for guests, or else you'll find yourself always having to wash them;
When it comes to wine, the most space-optimizing option is to get an all-purpose stemware set, and you should definitely take guests into account. However, if you're truly passionate about wine, consider having larger red wine glasses that allow their bolder flavor to emerge, smaller bowls for white and rosé as they maintain a cooler temperature and their floral aromas, and tall flutes for champagne and prosecco, which preserve the bubbles;
If you're after a versatile solution to save space, you could go for tumblers or highball glasses, that can be used both as an everyday item or to serve cocktails, spirits and mixers;
If you are planning on organizing some Gatsby-style parties, then you should look at sets of 12 or more;
As a minimum, have double the number of people in your household when it comes to everyday glasses, four for wine, and 2-4 glasses for the drinks that you enjoy more often.