While not essential, it’s a good idea to get an alignment with 4 new tires.
Experts recommend that you get your tires aligned once per year. If you just bought a new set of tires, you should get an alignment performed. Most places will include a free alignment along with the purchase of a set of tires.
Regardless, you should get an alignment if you’re experiencing pulling to one side or vibrations while driving. Hopefully, a quick trip to the mechanic will resolve your issues!