I personally get rid of the stuff that's a pain to adjust. Had some linear brakes once that wouldn't stay centered - OUT! GONE! I use the opportunity to upgrade both components. Also, it is amazing the stuff you discover when you work on the bike yourself. I had a frontt derailleur on a Stumpjumper that drove me nuts. I kept blaming myself because I was used to the primo shifting of the old Suntour XCPro stuff. When we finally worked on it ourselves we discovered that the derailleur was too high. We just kept playing with bolts and barrel adjusters, assuming the shop had installed it right.

You should be able to get some pretty decent deals on cranks about now. End of the year sales are abounding.