Good point Joe. Nice visual representation of the problem of donor limitation. I think the scale might be a little off though. My father is a norwood 5 or 6 and from where his hairline used to be to the top of the horseshoe in the crown is around 24cm, maybe 25cm. It's also varies width wise but I'd say he has a max of 230cm2 or at tops 240cm2 to cover. I think 240 is the number to plan for.
Some guys can get long strips. I could comfortably do a 32cm strip maybe more. I have heard that some of the lucky ones can have 3.5cm width extracted over 2 or 3 procedures. At a density of 85FU/cm2 which is probably about right for the average patient, and I'm going to say an extractable area of 32x3 (96cm2) over multiple procedures you're looking at 8160 FU. Of course some can get that 3.5cm width and some have big heads so they can take longer strips so they're total available donor will be higher. Plus higher donor density. I recall that NicNitro had a pretty long strip. Was it almost 35cm Joe? Sounds a bit ridiculous.
I've been told that the average patient has 8000-9000 available over a lifetime. Seems about right when pushed to the limit. Still let's go with 8160 for now and assume the 2.3 hairs per FU and average hair caliber.
240cm2 of baldness (norwood 6 land) and a native density of 85 pre mpb means 20400 FU lost.
However, in the first 65cm2 can have 45FU/cm2, the next 65cm2 can have 40 and the crown of 110 can have 30 for a total of 8825. Some could achieve that by strips and some might need another 750 FUE or so to get there. Sure that would mean a thin crown but I still think that's better than being slick bald.
Of course you do hear about people with around 10,000 available by strip and then another 1500-2000 by FUE. I'm looking at you Joe you lucky sod. 9500 with another strip of 1500-2000 and then another 1500 FUE left.
It's good to have good donor.
As Dr. Feller says you can have all the money in the world but if you don't have the donor there's only so much the doctors can do. For the real freaks out there, 50% density restoration all over is just about possible. FDR out.