Bro please take some time to read the threads already posted. Excellent answers to your questions can be found by using the search tool...
There is at least one entire discussion on this very topic. It's an interesting read.
Peace
Recycle. It's like a 30-35 year old woman. It gets better with age.
If you don't know that reference, or are to young to appreciate it, then you have not experienced the slip, and slide that you call the woman in her early 30's. :)