When you're talking about thick and thin in pottery, there are many different things to keep in mind at the same time. Here are a few. First, there's the aspect of developing skill. If you want to be versatile enough to throw thinly when you need to, then take whatever steps are necessary to learn to throw more thinly or you'll only be able to throw more thickly. Second, almost every pot needs to be thinner at certain places and thicker at others. For instance, if you're making a cereal bowl or a serving bowl, something that will see heavy use, the rim will need to be thicker in order to stand the abuse it's going to get. Some bowls you make, however, will have carved rims and will only be for display, so it will make it more difficult for you to carve the rim if it's thicker on that bowl. Third, some parts of your pieces should be thicker (and heavier) in order for them to be well balanced. I make pedestal bowls that have narrow bases and that flare out quite widely, so I keep more clay in the pedestal itself so it doesn't topple over so easily. Fourth, throwing is only part of the process of making a pot, and a pot's final weight and balance aren't only related to throwing. You also trim or carve and add handles or lids. Any of these additions or subtractions will make a pot heavier in some ways, lighter in others, and both can throw the pot off balance. I love to trim pots and see trimming as just another form of carving. Some people admonish potters to throw as thinly as possible in order to trim as little as possible and treat extensive trimming as if it's something you only do if you haven't thrown well to begin with. I don't see why anyone should accept this. Trim as much as you need to in order to get the pot you want. I'm a beginning potter and when I started taking pottery classes at the Hawaii Potters Guild I immediately ran into this idea that every pot should be thrown as thinly as possible. Like most beginners, I aimed toward that goal with absolute conviction, throwing every part of every pot as thinly as possible. Then one day I ran into a man who made ikebana displays at the Honolulu Museum of Art and taught ikebana classes at their Linekona school. I asked him to look at a few of my pots and tell me if they would be good to use in ikebana. He told me they wouldn't be good. Why? "They're too light," he said. He told me that another potter always came to the ikebana society he was a member of but that no one ever bought pots from him because they were thrown too thinly and weren't heavy enough. He explained that when doing ikebana, the branches or flowers were often arranged assymetrically and stretched far away from the pot. You needed a pot with some weight in the base to keep the whole thing from tipping over. So with his advice, I began making the bases of some of my vases a little thicker so they would be more appropriate for ikebana.