Reentry permit needed?

[boss351]

My family and I are permanent residents in the USA. My eldest daughter is about to leave the USA for University in the UK (she has dual citizenship, British and Brazilian). If I understand correctly from your page on help for the reentry permit, so long as she returns to visit us for short stays less than one year apart, she will not lose her residency status (even though the majority of the year she will be outside of the USA)? In that case, can she get by without a reentry permit or is there some minimum amount of time per year she has to be in the USA to keep her green card and residency status valid?

[immihelp]

Read https://www.immihelp.com/retain-greencard-useful-tips/