If your glassware is cloudy-looking or spotty, odds are good that you have two things: a dishwasher and a hard water problem. "Hard" water is full of minerals. In a dishwasher, the water droplets on the dishes after the rinse cycle will often be allowed to air-dry. When the water evaporates, the residual minerals are left behind, leaving spots and cloudiness.
What Do I Do About The Cloudiness?
If your glasses are already cloudy, you can make them beautiful again using a simple solution of vinegar and water. Use a spray bottle with the solution and a soft clean cloth to actually remove the deposits, and then rinse with plain water and wipe dry again with a new clean cloth before putting them away. Once they're sparkling again, you can use a spot-preventative in the rinse cycle, or you can be on hand when the rinse cycle finishes to hand-dry them with a clean soft cloth.
Is It Just A Cosmetic Problem?
The same minerals that are spotting your glasses are also running through your plumbing, which over time can result in buildup. Buildup can clog water filters, aerators, heating elements and shower heads, impairing their function. If you have a mineral issue, preventive maintenance is key.