How much salt do you put in a dish? Look at just about any dish requiring salt, and it will be specified simply as “salt”, or if you're lucky “salt to taste”. A complete cop-out. It's all the worse when, as in many cases, you can't tell whether the salt was right until the dish is finished.

This page suggests rule-of-thumb quantities for various kinds of dishes.

Dish		Proportion salt
dried beans		9%