Lifehacker.com article about decluttering.

Three questions gives good advice also:

If you had to purchase the item yourself, at full price, would you?

If someone you didn't like gave you the item as a gift, would you still keep it?

Does the item invoke happy memories?

If you answered no to any of these questions, consider getting rid of the item.

And here is the one-fell-swoop approach based upon a Japanese author of a book popular in Japan, Germany, and the UK. I wonder why it missed the US?

SRS