After 7 years it will be dropped. It makes no sense to pay it, after it already goes to collections and impacts your credit score, because even if your paid it off, the company will not remove it. (i learned the hard way).
After 7 years it is removed, and cannot be placed back on.
I disagree. While negative information must be removed from your credit report after 7 years, that does not mean the lender or medical provider must stop trying to collect at 7 years. And the 7 year clock on your credit report only starts when the lender gives up and charges off the debt. Suppose they try to collect and keep the debt open on their books for 5 years, that means it won't drop off your credit report for 12 years in total. Plus, whenever the debt is canceled (let's say, after 5 years) it becomes taxable income to you and you have to pay the IRS or they will come after you too.
You really should pay what you can, being current on an agreed-upon payment schedule is a plus for your credit report even if it takes a long time to pay off. Or, ask them how much they would take as a lump sum now to cancel the rest. That at least would start the 7 year clock now instead of years from now.