Worried that... You might need it someday?
If you keep everything you might need someday, you're going to need a warehouse. If everything seems potentially useful, maybe you're not sure what's truly important to you. Think about your hopes and dreams. Then identify what items or information will support you in achieving them. Without knowing this, all of your stuff can seem worthwhile.
AVOID CREATING A NEW GOAL TO JUSTIFY PIECE OF CLUTTER,
Worried that... You paid good money for it?
Just because you bought something doesn't mean you have yo keep it forever. If you used it, you already received some return on your investment. If you didn't, it's okay to admit it was a mistake and move on. In reality, getting rid of the item ( by donating it and taking a tax deduction or by selling or consigning it) is the only way to recoup some of the money you've already spent and are continuing to spend in order to house it.
IF YOU'RE NOT USING AN ITEM, IT'S NOT PAYING YOU BACK.