United Airlines can be very reluctant to add you frequent flyer miles to your Mileage Plus account after a big trip. Those of you saving your miles for a free trip should check and manually request mileage credit for all of your flights (including connecting ones) 15-30 days after you return.
Failing to do so could mean you will not be able to redeem miles that have expired outside of the 30 day window. Keep in mind that United miles expire after 18 months and should be donated to charity if you can’t use them.