Patchiness is the results of not overlapping. They should be overlapping and you should see good shedding of pretty much everything 3 weeks after the treatment if it's done well. It's all in the technique.
Overlapping is VERY important on the fact if you want to avoid the weird patchy look.
Hi everyone. English is my second langage so some parts might not be very well written or precise, sorry for that.
I'm new here and by no means an expert.
Most of the thing I know, I learned it here and on couples of other board.
On the other side, as a customer, I think i have now an extensive and somewhat different experiences than most and i will give my personal feedback.
I'm a 40+ year old male. Dark skin (between 3-4). Thick dark coarse hair all over, I need to shave again at night to look "kind of clean".
In 2009 I had my backs and shoulders done, in a prepaid package of 7 times with a very reputable company (epiderma) with the lighsheer ET (no ideas of the settings). It worked great (95%+ reduction). The remaining hair are thin and almost invisible. I did 2 more treatment after that on the back but I stopped because these remaining hair will not go with laser and i'm a little scared of inducing those evil hair.
In the summer of 2010, I decided to go for a laser run. I started doing the whole front part from the beard to the bikini and everything in between. Also add arms and underarms.
I switch clinic because the previous one only offered 7 meetings program and I was not sure if I wanted only reduction versus eliminitation in certains spots.
Before going on with it I made a lot of research (here) and made my own plan.
I am in a special situation. I have big time constraints in certain period of the year. Plus time played against me because at my age white hair we're starting to grow at an alarming rate, those considerations we're the most important one AND money was not even a consideration !
People recommends to have treatment every 6-8 weeks with a possible touch up after 3 weeks.
Since money was not an issue, time was short and it was a nice free window of time for me in an otherwise tough schedule to deal with. I decided to not ask for any small area touch up but to go for the whole thing every 4 weeks.
Since it did not look to be dangerous and I did not care if I was trowing part of that money away, i thought it was the best way to avoid missed spots. I was also going to 2 different place with a different technician to make sure the same "mistake" won't repeat over and over (always missing the same spots)since their method will be somewhat different.
I now had 5 or 6 treatmentn on all of these bodyparts (the first 3 with the lightsheer ET and the last 3 with the lighsheer DUET (no other than lighsheer are available in the area, might try an ND;YAG about 200 miles from here soon).
Most bodyparts, stomach chest arms underarms responded very well. I never saw patchiness or missed spots.
The beard (and part of the bikini) have always been patchy (done by the same technicians than the rest).
Considering the fact that I was on an accelerated schedule (to avoid missing spots) that I used different technicians and 2 differents laser (the DUET is way bigger and should not "missed" the same spot the ET did), and considering that we made sure to overlap a lot on the major resisting area (visible patch)in my face, I would have to disagree with you that patchiness is only bad overlapping or technician related (not saying it is never that, might be the case quite often), but I think there is more to it (either those hair are depper root and diod can't get them or something).
Actually my point here is not to debate you (who knows thousands times more than I do) but I think that practically speaking, whatever the reasons, someone going for the beard have a strong possibility to come back with patchiness, so be ready to live with it...on the other hand, trust me, it's worth it (shaving is now way smother).
As another update, I suppose to show commitment, I also do electrolysis (with a very experinced technician)for the white hair in the beard (of course, we see them more then ever with less black hair surronding them)and went trought couple of session already(1 session lasted 4 hour on the beard ouch).
That was my experience up till now. Hope it helps.