you will know when you need an alignment because the car will not track straight, will pull to one side, or you'll see uneven wear on the tires.

Just get your free services from them and decline everything else because they will rob you blind.

Find a trustworthy independent mechanic who will give you honest 2nd opinions.

The dealer is going to recommend anything and everything, even beyond what is in the owners manual. And even if you don’t need it.

Follow the maintenance schedule in the owners manual. 

The part you said they recommended a wheel alignment but out of your own pocket means it definitely wasn't needed and they just wanted to make money. I say it definitely wasn't needed because a dealership told you this and they're known as stealerships. Always Have an honest independent mechanic check before accepting what a dealership tells you.

Generally no, not at that mileage. It's the typical up-sale for services that usually don't need to be done. It's for the service writers to make more $$. If the car isn't pulling to one side or the other, tracking straight, and tires are wearing evenly (keep rotating them regularly) then an alignment isn't necessary. 

Agree with others. Unless you know you "wacked" a curb or massive pot hole. Otherwise if he drives smooth and straight its a pass.

In the future if you ever need it, do not go to dealers. Go to a good alignment shop for a better service with less cost.

Typical dealer rip off tactic.

I also went to the dealer for free service and they tried to sell me the same thing at 18000 miles. Supposedly the dealer said Toyota suggests a front end alignment and the wheels balanced at that time.  A pure scam. My tires have been wearing perfectly and the wheels don't shake.