Have you had the carpet professionally cleaned? If so, and it remains stained (and/or worn), then replace the carpet with something that coordinates with the existing basement carpet. Keep in mind that you might choose to replace the basement carpet at some point. And may need to recarpet the stairs...

Thank you. I aporeciate the suggestions. I have used a variety of carpet cleaners on stairs, but will call in professional cleaner before replacing carpet.

Just as a point of interest, most carpets have a 10-15 year lifespan. Even though the carpet LOOKS to be in great shape, the amount of dirt, dust/allergens the carpet is hiding/holding on to will be significant (after 16 years).

As much as you may not want to face the inevitable, the carpet is at the end of it's life. The stairs are simply showing it more than any other spot.

You are welcome to get the professionals in to do their magic. But be aware an ENTIRE replacement is JUST around the corner (next 1-2 years). If you replace the stairs NOW, you will find yourself in a BAD situation in 2 years....you will NOT find the matching carpet. I can guarantee it.

Man-made flooring products (carpet, lino, vinyl, engineered hardwood, vinyl plank, laminate, etc) have a shelf-life of 18 months (or less). That means you will spend money today only to have to spend it AGAIN in 2 years because nothing matches.

And if anyone in your home has breathing problems, high blood pressure or heart issues, then replacing 16 year old carpet is a great way to make your home HEALTHIER. You will be AGHAST at how much dirt the shop-vac will pull up once the carpet is removed. It's enough to make health-care professionals gag! I've seen a single room (with 18 year old carpet) give up 5 shop-vac containers FULL of debris. It is disturbing.

Carpet on stairs, especially going down into the basement, is a health hazard and an easy place to catch a shoe and trip.

Thank you to all who have responded. Definitely appreciate the help in order that I make the right decision.

Maybe look into replacing the carpet with vinyl plank and then just having a nice area rug and a runner on the stairs that works with the area rug. I actually do not find stair runners all that much of a tripping hazard but I really hate wall twall carpet it holds onto all kinds of yucky things including dust.