No mystery to it. Here is exactly what happens from the moment you call to the moment we hand the job back.
The cleaner measures, identifies fiber and soil type, and points out what will not come out. Price adjustments for stains, stairs, and urine should be settled before work starts.
Dry soil is vacuumed out, then a pre-spray matched to the fiber is applied and left to dwell. Cutting dwell time short is the most common corner cut in this trade.
A counter-rotating brush or grooming rake works the pre-spray down to the base of the pile so that the extraction pass has loosened soil available to pick up.
Solution is flushed out with heated water, usually followed by an acid rinse on residue-prone fibers so nothing sticky stays behind to attract soil over the next few weeks.
The pile gets set upright, air movers go down, and the cleaner walks the job with you while the carpet is still damp, so touch-ups happen before the equipment leaves.
None of this is required — it just makes the visit quicker.