if you hit something..
it really depends how you drive, some vehicles dont need to be touched, ever. I only align my truck when I get new tires, about every 60K miles, and even still, it doesnt really need it... but we have had several cars that need it more often than that. every 6 months, or so.. you can tell by the wear on the tires.
Yes
new tires does not mean you don't need alignment. it is always a good idea to have the vehicle aligned after new tires are purchased to avoid premature wear, even if the car shows no sign of mis-alignment.
Doesn
Not necessarily. If the car was in alignment prior to getting the new tires, it will be in alignment after the new tires. It isn't a bad idea to check the alignment periodically and it is probably better to check it more frequently than when you get new tires.
every time you get new tires and when you hit a really hard pothole, when your car starts pulling, or if your in a collision.
No. If there had previously not been any alignment issues, and as long as the new tires are properly balanced, you will not need an alignment.
You sould have the new tires mounted FIRST, then have them do the alignment at the same visit.
If it is brand new - no. But - things do go wrong for whatever reason. New car should have a warranty.
go get 2 new tires and have the alignment checked on it
After
I'd at least have it checked, just to be sure everything's fine
Tires and alignment are separate things. Each new tire needs to be balanced after being mounted on the rim. This makes sure they don't vibrate and wear unevenly. Alignment on a car has to do with where the wheels are pointed. The angle of all wheels should be perpendicular to the ground under its own weight. The front and rear wheels, from one side to the other, should be pointed down two lines that are perfectly parallel. Bad alignment on your wheels will show up in the tread wear. Wear patterns can identify what is wrong with your alignment.