Visit Re-Entry Question

[abc_usa]

Hi,

My parents came to USA last year from July 2015 to Oct 2015. (4 months). Now I would like to invite them again.
- What is minimum time they should wait?
- how exactly 6 months in year works? they consumed 118 days out of 180.
- Can I invite them in mid April-2016 for 4 months?

Does anyone see issue here?

Thank you for inputs

[immihelp]

There is no specific rule or set rule for visitor visa.
Visitor spend most of their time in their home country and 6 months gap is advisable.
You can invite them in April and their duration of stay will be determined by POE officer.