How often i have to do wheel alignment?

It's a good idea to have your wheels aligned whenever their alignment changes. Your alignment changing depends largely on how you drive your vehicle. Generally, it's probably a good idea to get your tires aligned at the same time as you rotate them.

Look at your tires, worn off on the inside or outside of the tread? you need alignment. Worn off in the middle of the tire, too high of tire pressure. Scalloped looking on the edges, you need shocks. If you like to "find" the curb every time you park your car you will need alingnments more often. Dodge holes in the road and stay away from curbs and if the tires look good, don't sweat it.