How many grafts can be extracted from the donor area in a single operation and all in all?

[Zyad]

Is it possible to undergo a second hair transplant 1 month after the initial operation for a different area of the head? I have had my first operation to increase hairline density 10 days ago and i realized my mid-scalp and crown area are extremely thin. My job’s nature hinders me from cutting my hair that length again so i was wondering if i can undergo second one without having to wait another year. 
Also, if follicular unit grafts were transplanted in exactly the same spot as in the first session, would that damage the previous ones?

[MAIZE1694]

How many can be extracted ethically or in total?

Avg guy probably has 10-12k usable grafts? It varies.

After about 7-8k grafts the average guy would start to look ridiculous from the back with hair length < 1 inch. 

[Gatsby]

42 minutes ago, Zyad said:

Is it possible to undergo a second hair transplant 1 month after the initial operation for a different area of the head? I have had my first operation to increase hairline density 10 days ago and i realized my mid-scalp and crown area are extremely thin. My job’s nature hinders me from cutting my hair that length again so i was wondering if i can undergo second one without having to wait another year. 
Also, if follicular unit grafts were transplanted in exactly the same spot as in the first session, would that damage the previous ones?

I wouldn't recommend surgery only 4 weeks post op. The scalp and grafts need time to heal from the trauma. Plus regardless of the area you want to give the first transplant time to know what is doing what before committing to a second surgery.

[Doron Harati]

After 8-9 months you can have another HT, you don't want to over traumatize your scalp, never do cosmetic surgeries under pressure.

[AlexGSwe]

If the crown si untouched you can do it again in theiry however it is better to wait. And always remember the donor areas can not always promise that you get double or triple grafts which is needed in this areas you will get some singles also always even with different pre extraction examinations with microakopes, and it is shame to throw them away you WANT them for your front line in the future and yes you cant put them there now because you have grafts there recently planted in the areaa. I hope this helped.