Negative Items remain on your credit report for 7 years from the date of the negative item. So if the account was "charged-off" it will remain on the report for 7 years from the date of the last delinquency(missed payment). It does not mean the debt goes away, it just means that the creditors can no longer report it to the credit reporting agencies(TransUnion, experian, Equifax).
Creditors, and collection agencies, can not re-age a debt. So it does not matter how many times they transfer it, the date that matters is the original delinquency date. If she has debts that are more than 7 years she needs to send a dispute to the CRA's to have it removed.
Now there is another item called the legal Statute of Limitations. This is a point after which they can no longer force you to pay by filing a suit against you. This is usually 3-6 years depending on the state you live in. So if she has them in the 4-7 year range there is a good chance they are outside of the SOL and can not take any legal actions. The link below gives you a break-down by state.
If she does want to pay them off, only communicate through the mail, NEVER negociate over the phone. Have her send her offer with what she can pay each month. Also, include that once she pays it off that they remove the collection account. DO NOT send any money to them until they have an agreement in writting from them that they approve.