Yep, deshbhaktanepali is correct.  You don't get whole bunch of 29 months OPT when you apply for OPT.  When you first apply you will get 12 month of OPT and the 12 month limit on OPT gets extended by 17 months, for a total of 29 month, for only STEM degreeholders who are working for a US emplyoer in a job directly related to their major area of study.  And yeah note this if you are unable to find a job within 90 days from the start date of your OPT, your OPT becomes invalid meaning you are out of status after three months according to this new rule.  So I believe there is not whole lot reason to be happy with this 29 months OPT rule.