To XBT and all Da Xia

H1b used 5 year right now,is going to expire, but 140 approved two yrs ago and 485 peding for two years
at this point, should I renew only one year to used out the so-called 6 yrs limit, and one year later renew 3 yrs, then renew another 3 yrs....
2.or at this point, I can direcly renew 3 yrs?
Pls advise. many thanks for all