How many 100g packs of PH will I need?

That's 50mm that was hand blended in 70% Vanille, 10% Platin Blonde, 10% Satin Blond, 5% Seiden Blond, 5% Blond, and trace amounts of Creme Weiss UV to pick up light. You don't have to hand blend it because if you ask Sara, she can have this color custom blended for you in these percentages.    

I didn't wash mine for 7 days after the install and I think that really helped it to set. I'd just wash the crown area. But later, I washed a couple times a week, then 3 times a week. Toward the end of 3 months wear, I washed every other day and I was really pleased with the softness. I used nothing more than regular shampoo and a super thick conditioner like Feria. ALWAYS squeeze products into the hair (some call it sponging), and never massage it in. I never ever had tangles even with super long length.

I personally like to layer it before. Since I'm growing my hair out and it's getting somewhat long, I don't want my real hair getting thinned with the razor as the install hair is getting blended in. If there's any odd lengths and stragglers that shouldn't be there, I snip them down.

Plastikhaar should only be cut when completely dry, imo.

Edited by amm

Amm, what's that colour called in the picture?

It looks so shiny and as though it won't tangle, I ordered 3 different colours of plastikhaar black, brown and red, some tangled more than others, such as the black was alot more tangly and a bit dry than the red.

Yeah, I'm just looking for "middle of the back" kind of length. (does it
take more for butt-length because it takes more installs to make it look
natural with the super long length? or cuz with mid-back length you can
cut the PH in half for 20 inch pieces?) Helpful info, thank you so much!

It can take anywhere from 2-3  packages.  When I have applied it on clients, I am usually  mixing about 3 colors, and when we are done, I'll have just a bit of each color left over.