I have some clicking going on in my rear gears. It's indexed 7-speed in back, friction 2-speed in front. I am mechanically inclined, but haven't done this before. How can I determine whether something is just out of alignment, or if I need new parts?

worn out means the pivots are sloppy. alignment is checked with the alignment tool

Netdewt, It may not be out of alignment, but out of adjustment. Take a look here: https://www.parktool.com/blog/repair-...nts-derailleur .

Brad