Depending on the type of account, it can take anywhere from 3 to 10 years after the account is paid and closed, before it falls off the report. For things like a 12-36 month signature loan it's usually around 3 years after the last payment is made, before it falls off your credit report. Whereas something like a mortgage can hang around for as long as 10 years after it's paid off. For an account that it "charged off" the average is 7 years. That's usually something like a credit card where the credit source has given up trying to collect what you owe them, and they just write it off as a loss. Those charge offs take on average 7 years before they fall off your credit report.

I have heard mixed views should I attempt to settle or pay in full any accounts in collection? I had a few settled on them and it was never taken off my credit and switched to a new collection agency. Just want to know the best option to fix my credit

A credit report is basically a "history" of you making payments on debt that you are obligated to pay. Of course, not paying the debt in accordance of the agreed upon payment terms is a "bad" history. The longer the debt goes unpaid past the agreed upon payment terms, the worse your credit will be, and the worse it will continue to get.

Paying off the past due debt will not, in any way, form or fashion change your payment history. It does however, keep your credit from getting worse. Then as time goes by and that paid off debt gets older, it holds less and less weight on your credit "score". So if you have a credit score of say 500, paying off all your past due debt today will not make your credit score go to 800 tomorrow. It will still be 500 tomorrow.

But six months from now it may be 550, then another six months it may rise to 600. That is of course, assuming you don't get behind on any other stuff during that time.

Bottom line is, the only way to "fix" your credit, is to first pay what is due and past due as fast and as soon as possible. Then the other ingredient is time. You have to wait. During that time you're waiting take out some cheap debt, such as a credit card with a $250 limit. Then before you use that credit card to buy something, (such as gassing up the car each week) make sure you have the cash in you pocket to pay it in full when the credit card bill arrives at the end of the month. Then pay the balance due in full.

That will appear on your credit report too, and will do two things:

1) It shows that you are "growing up" and starting to act responsibly with debt.

2) It helps your overall credit score to start rising sooner.

I have a family member who got divorced in Dec of 2017 and because their ex was very irresponsible with debt, their once perfect credit score was a 580. As of Oct of 2018 their credit score is up to 680 now. So once you've decided to be responsible with debt (and it sounds to me like you have now) it just takes time.

I have a similar question, how long does it take for a repossessed car balance to come off your credit report??

There are some charge off accounts on my credit report that should have fallen off a few years ago. Is it possible or legal for one collection agency to pass it to another and keep it “open” or going for longer than that time frame?

Yes it is possible  they can sell it to another collection agency