h1b requires you to stay employed at the same company. There are some exceptions to change company but its a complicated process. You need 5 years in the US to

h1b requires you to stay employed at the same company. There are some exceptions to change company but its a complicated process. You need 5 years in the US to be granted a green card. h1b are valid 3 years. Generally you need 2 h1b to get a green card (of course you start the process much before the h1b ends) if you are in a gc and you stop working in the us for a certain amount of time (i forgot, but its not longer than a year), then you start over and the gc is terminated (you need a h1b again) For citizen, its 10 years. h1b specifies AFAIR that once you're unemployed you have to leave the country immediately without citing numbers albeit 30 days sounds reasonable.