Can you get the american opportunity credit more than once?

Q.  Can you get the american opportunity credit (AOC) more than once?

A. The student or his parents, if they claim him as a dependent, may claim the AOC up to 4 times. 

Q. Can you claim the AOC if you didn't get a form 1098-T?

A. It depends. A form 1098-T was made a requirement for the education credits a couple of years ago.  However, if you qualify for an exception, you may still claim the AOC, without a 1098-T.  If you attended an eligible institution, you most likely qualify for an exception. 

However, a taxpayer may claim one of these education
benefits if the student doesn’t receive a Form 1098-T because
the student’s educational institution isn’t required to send a
Form 1098-T to the student under existing rules (for example, if
the student is a nonresident alien, has qualified education
expenses paid entirely with scholarships, or has qualified
education expenses paid under a formal billing arrangement). If a
student’s educational institution isn’t required to provide a Form
1098-T to the student, a taxpayer may claim one of these
education benefits without a Form 1098-T if the taxpayer
otherwise qualifies, can demonstrate that the taxpayer (or a
dependent) was enrolled at an eligible educational institution,
and can substantiate the payment of qualified tuition and related
expenses.

https://www.irs.gov/pub/irs-pdf/f8917.pdf