Piled all your items into a bin for security scanning? When you pick it up the other side do not just empty it and walk away in the happy belief that you left nothing behind. Wheelchair pushers (when you're not looking) and Security staff have a habit of moving some of your kit into separate bins. That's how 2,000 items a month end up in Lost Property at Orlando. Probably the same worldwide.
Better yet, instead of emptying your pockets into those bins, try putting everything in your carry-on or personal item BEFORE you get to security instead.
I am flying to Montreal next week, going through Philadelphia. Do I go through customs in Denver or Philadelphia... or not at all.. just have my passport with me? I am a TSA Pref passenger. Thanks for your advice!
There is no US Customs when leaving the US. On your way to Montreal you will go through Canadian Immigration and Customs in Montreal. On your way back, you will pre-clear US Immigration and Customs in Montreal.
Flying to Florida in April and again November from Chicago 2016. Am I going to need a passport?
You will not need a passport in April. It is not known yet if you will need one in November. The TSA says it will give 120 days notice if they will stop accepting any drivers licenses. They as of yet have not given any notice to that effect.