[brakey]

Fact of the Matter is that "IF" you see unusual wear on the front tires you may need a wheel alignment.
No you don't need an alignment periodically unless you want to support the local wheel alignment and tire shops with additional profit.
Running counter clockwise on the roundabout's may or may not cause tire wear on the right front tire. Cornering force will act on the outside edge of that tire but tire wear in this case will be dependent on your speed through the roundabout. It depends how aggressive you are.
Generally wheel alignments are needed when some front end component is damaged or worst case if a front end part is bent from going off road, into a curb or some other obstacle.
The best way to determine if you need a wheel alignment or wheel balance is to monitor tire wear. You can google tire wear or pick up an automotive book that describes what tire wear to look out for and what to do about it.

ASE certified master mechanic and Automotive Engineer