Can someone objectively explain what happens if I do NOT apply for 3-year extension of my expiring H1B? Do I lose it?

[joas]

The situation:

I am waiting on my I-485 (AOS). I am EB-2 ROW so I am expecting to get my Green Card sometime around January if I am lucky and if the priority date becomes current again in October.

My simple question:

What happens if I do NOT extend my H1B? Do I lose it, meaning if I ever want to go back to H1B I have to ask for a new one through the quota? Do I not lose it but I will have to exit the country to get a stamp and come back if I ever want to reactivate my H1B for the remaining 3-year extension?

I have only used 3-years of my h1b and it is expiring this coming October.

Is it better to request the 3-year extension or save the 3-year extension if I ever need it in the future?

Let's assume that my AOS will eventually be approved since I am a good citzen without any problems with the law.

Is it a good idea to extend my H1B or stick to EAD + Advance Parole?

Many thanks!