conversation: User (theotherredmeat): "Looking over my portfolios there are 2 or 3 funds that have been doing terrible and likely won't bounce back to even put me in the black anytime soon. I can't help but thinking to dump and run and reinvest if what looks like greener pastures. \n\nSo when do you know when is when to pull the plug. Any personal systems you may use or particular methodology?"
  Self: "Honestly if you have "stinker stocks or funds" you're probably not invested in the right things to begin with.  You should be invested in broadly diversified index funds that you hold for decades regardless of performance.  You should only be making asset allocation changes because of changes in risk tolerance, not performance."
  User (theotherredmeat): "These were some older purchases and I have become a lot more wise in the past few years.  These are stragglers that I've let linger too long and should probably be converted to a better long term index fund. "
  Self: "Then I'd just do it now.  You can write off losses on your taxes to offset capital gains or income up to a certain amount.  Make sure you don't run afoul of the wash sale rules if you do that."
  User (theotherredmeat): "Thanks, I know you are a go to guy (or woman!) around here.  Can you tell me more about what a wash sale rule is ? "
  Self: "If you buy a substantially similar security within 30 days of selling another one at a loss with the intent of claiming the loss on your taxes, that is a wash sale.  There are penalties involved that I can't remember at the moment."
  