Go move your heaviest armchair a foot to the left. Look at the carpet that was under it, then at the carpet right next to it.
That gap in color is the dirt your vacuum hasn't been getting. Most people are a little startled the first time. It's also the simplest of the five signs below, and the one that tends to send people to the phone.
1. The house makes you sneeze more than the yard does
Spring in Chapin means a yellow film of pine pollen on every car and porch rail, and on the dog. Some of it comes inside on shoes and fur, and carpet is very good at holding onto it. All of it settles into the pile along with dust and dander, and every footstep kicks a little back into the air.
If someone in the house sneezes more indoors than out, or wakes up congested in a carpeted bedroom and feels fine by lunch at work, the carpet is a reasonable suspect. Vacuuming helps with the top layer. It doesn't reach what's packed down near the backing.
We won't promise a cleaning cures allergies. It won't, and anyone who says otherwise is overselling. But removing what the carpet has collected is one of the few changes inside the house that people say they can feel.
2. Stains come back after you've cleaned them
You blot the coffee and it disappears. Four days later there's a brown shadow in the same spot. That's called wicking. The spill soaked into the backing or pad, and as the carpet dried from the top, it pulled the leftover stain back up the fibers.
Heavy scrubbing and soap-based spot cleaners make it worse. Scrubbing spreads the spill, and the soap leaves a tacky film that grabs new dirt, so the spot ends up darker than before you started.
One stain that returns is annoying. Three or four of them in a room means the problem is below the surface, and that's where professional cleaning earns its price.
3. Rooms smell stale even when they look clean
This one creeps up on you, because noses adjust fast. Guests notice it before you do. Coming home from a weekend away is the other time you catch it.
Carpet holds onto food spills and body oils, plus whatever the dog brings in, and in a humid summer all of that gets a little riper. Candles and plug-ins only add another smell on top.
If the odor gets stronger near where the dog sleeps or on muggy days, you're probably dealing with pet urine in the pad, and a pet odor treatment is what you want. A general mustiness across the whole room usually comes out with a regular carpet cleaning.
4. The traffic lanes look flat and dark
Every house has a map of where people walk. The front door to the kitchen. The couch to the hallway. The top of the stairs. Those paths start to look darker and feel flatter long before the rest of the carpet does.
Some of that is dirt, and some is wear. Fine grit in the pile cuts at the fibers every time it gets stepped on, a little like sandpaper. Clean it out regularly and the lanes stay closer to the rest of the room. Leave it for years and the lane stays visible even after the dirt is gone, because the fibers themselves are damaged. A cleaning can make a worn lane look much better. It can't make it new.
Our rule of thumb: if you can trace the family's routes through the house by looking at the floor, it's time.
5. The dirt you can't see
Back to the armchair. Carpet is very good at hiding soil, and darker or patterned carpet is the best at it. Skin cells and crumbs work their way into the pile along with clay from the yard, and the surface still looks reasonable.
That's why we'd rather you clean on a schedule than wait for the carpet to look bad. By the time it looks bad, it's been bad for a while. For most homes, every six to twelve months is about right. Pets or young kids push that closer to six.
If you saw two or more of these signs in your own house while reading this, you're probably due. Three rooms are $88 on our coupons page, and the online scheduler shows open times. Put the armchair back first.