Cleaning a 15 year-old carpet

This afternoon I worked for one of my returning customers.  Their white nylon carpet is now fifteen years old and still looks so nice after cleaning.  They were thinking of replacement, but are so happy to have the carpet looking clean again.  Two weeks ago I cleaned all their tile and grout.  It was the job where I mentioned I forgot to take before/after photos.  The tile and grout looks new.  A great deal of satisfaction comes from a job well done.