Permanent Hair Removal is a team effort between practitioner and client. Sometimes it also requires a team that includes a doctor and a nutritionist.
There are many variables that come in to play when it comes to what is possible with a hair removal project. Practitioner skill and chosen method is one thing, and client scheduling is very important as well. The amount of hair and hair growth cycles also make one job very different from another. Some factors can also be deceiving.
Many people THINK that they did not get good hair removal treatment, when in fact they did not stick with it long enough to give it a fair shot. Others are following a schedule and or program/method that won't give them a steady visible progress fast enough for their taste. Many people THINK "all the hair grew back" 4 to 6 weeks later, when that is in fact just the next phase of hair growth. No one would take a before picture, do the treatment, take an after picture, and then wait a year to take another after picture to compare in order to "test electrolysis efficacy" yet that would be what would be needed to really see the effectiveness of one treatment in truth.
A little story to illustrate.
There once was a client who had a unibrow that was as bushy as privacy hedges. The treatments were done in such a way as to fully clear out the unwanted hairs and shape the brows as opposed to the gradual reduction technique that many (most?) would employ in this area. Although the first and second clearances came with angry red and swollen skin, the client was happy with the initial results.
A life changing event had the client move unexpectedly to another state, and in the new home did not find anyone who impressed the client enough to continue the work that had been started. So, the project was shelved.
As the fall came, the once movie star shaped brown became unkempt and by the dead of winter were once again a unibrow. The client was dejected thinking about the money "wasted" and felt as if there was no hope for the future, until the rays of spring started to come. As the anniversary date of the work approached, the bushy unibrow began to thin, subside, and finally, opened like a curtain. The movie star brows were back! They stayed that way all spring and summer, every year with certainty, just as the winter bushy unibrow came again during the untreated growth cycles.
The client called the practitioner to tell the story and to say that since the winters were spent with a hat on all the time, it did not matter about the unibrow during those months, since the prime time spring and summer were secure from that pesky unwanted hair.
And the client lived happily ever after.
(Yes, this is a true story)
Your prescription above to judge a patch test 3 months later would show variable results based on how the treatments were done, and what body part the test was done. While one might see some varying degree of reduction or not, it won't be the same as the view of that patch 365 days later.
Since most people don't want to make an 18 to 24 month process become a 36 month process, they generally are best served by choosing someone they trust and giving that person at least 12 months to show some results. If one's practitioner does full clearances in 6 weeks or less, it will be about the same as getting the entire area cleared out in one day or three as long as one sticks to the schedule. If the practitioner follows the skip around method, one won't really have a way to judge reduction for a good long time - especially if one is only getting one hour every 3 weeks.