Do I need to update ESTA for each trip?
Do I need to update ESTA for each trip? Your ESTA authorization is generally valid for multiple trips over a period of two years (starting the date that you are approved) or until your passport expires, whichever comes first. As long as you received an ESTA authorization to travel, you do not have to reapply during the validity period.
How soon can I reenter the US on tourist visa?
There aren't any rules or laws requiring you to wait a specific time before you are allowed to return. What you must remember is staying the maximum time during your previous visit and then wanting to return soon after that might raise suspicion with the immigration officer.