How many times do anda think a person needs to read Harry Potter before they can completely understand it?

Depends completely on the person. Some people ate able to comprehend things faster then others. Some people have trouble reading. Some understand sifi atau romance better then fantasy. Everyone's membaca style is different.

Once

I think if anda read it once anda will understand it one way, if anda read it twice anda can pay attention to things anda did not pay attention to first time anda read it and maybe see a lot of things differently. Because HP has depth and layers.

However many times the person thinks necessary.

I only read the series once and I'm pretty certain I got everything down. There hasn't been a single thing that anyone has mentioned that I didn't catch. It all depends on how much attention anda pay.

Just once, it's not that complicated.

once. but it never hurts to read it over and over (and over...) again :D

Just the once.