If the old tires are worn unevenly, less tread on one side of the tire than the other, then the wheel alignment is bad. Get it corrected when you get the new tires fitted so you don't wear the new ones out prematurely.

If the tires have worn out evenly, and the car is driving straight, chances are the alignment is fine and you just need new tires.

It's always wise to get the tire shop to re-align the front wheels. If it's out of true your new rubber will just wear away faster.

Wheel alignment is worth checking if your tyres have been showing unusual wear pattern, such as wearing on one edge. If your tyres have worn evenly, there is no reason to think the alignment is wrong. Simply fitting new tyres will not affect wheel alignment.

Are you replacing the tires because they got ruined by a bad alignment? If so, get an alignment. Are tires worn evenly?

Drive on a straight road and hold the steering wheel straight if the car is taking a side then you have to do it , otherwise no need, dont forget to do wheel balance, thats important

*Only if there is any unusual tire wear on any of the four old tires.

you SHOULD get one so the new tires don't wear unevenly