As you may know, carpet is dyed and the dye can be removed or altered by many things. The most common are Bleach, Peroxides, Pet Urine, spot cleaning with high alkalinity spotters and Fading.
Redyeing just the affected areas is very successful and colorfast when it's done by a skilled technician. It can however be a disaster if attempted by the "Do-It-Yourselfer" or the carpet cleaner.
Dye is not like paint that can cover up one color with another. It's transparent and the color of the damaged area must be calculated into the dye mixture so it combines with it and becomes the color of the original carpet.
The cost of carpet replacement today is anywhere from $600 to $1000+ per room. Most often carpet "uglies out" before it "wears out".
Many times it can be re-dyed to new like condition for a fraction of that price. I have saved people tens of thousands of dollars with my process of color restoration.
Text me a couple pictures of the spots so I can see what you have , and I'll reply with an estimate to repair them.
Send to: 714 928-3876
I have over a dozen ways of applying carpet dye, here's one of them.
The blue dye combines with the orange spot and turns it back to the original color. Groovy huh?!? =]
Check out this great video