> H-1B visa holders are REQUIRED to leave the country to renew their visas every few years
This part is not exactly true. You can renew H1B indefinitely within the USA(every 3 years, need a pending Green card application from the 2nd extension onwards i.e after 6 years). However, if you leave the US for any reason you won't be able to re-enter the USA without a renewed visa stamp from a US embassy. The two exceptions are that you can visit Canada or Mexico for less than 30 days without triggering the visa stamp requirement.
No, it's correct. The original comment said "to renew their visas". The visa expires on its expiration date, however the H1B status itself is extended. Hope this helps.
This part is not exactly true. You can renew H1B indefinitely within the USA(every 3 years, need a pending Green card application from the 2nd extension onwards i.e after 6 years). However, if you leave the US for any reason you won't be able to re-enter the USA without a renewed visa stamp from a US embassy. The two exceptions are that you can visit Canada or Mexico for less than 30 days without triggering the visa stamp requirement.