Originally Posted by
TWA Fan 1
I don't think it's meaningless, since, if the OP's bag(s) must be checked, then, if he/she has a tight connection, this could result in the bags missing the connection.
If the carry-on is near the size limit and thus may not fit in the older-style 738/9 interior overheads, then there could be a problem.
It is indeed meaningless, because the answer does not affect the recommended course of action. OP should
not check his bag if there is a tight connection at EWR. Ergo, he will have his bag in hand when he boards the flight to SJU. Either it will fit overhead or it will not. If it does not fit, it will be gate checked. Either result - bag in overhead bin or bag checked at the gate - is preferable to having it miss the connection at EWR and thus end up in baggage limbo.