The more I think about it, you might have lets say, 10-20 ECA for your application, and by all means if you do, put them on your AADSAS.
Keep the following in mind though:
1) ADCOM see thru your bull**** ECA, so don't write something on there that has a terrible description. In addition, if you do put something on there, be prepared to answer questions and explain it in the context of an interview. Make sure the details you provide here are the same in your AADSAS or you will be caught in a lie.
2) In the course of an interview questions about your ECA are bound to come up, either directly or indirectly. You'll likely only be able to talk about 1-2 of the things you've done, so prepare carefully about which you are willing to discuss, and make sure that they place you in a positive light.
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