You're fine. Unfortunately I don't remember. I don't have a good memory in the first place and I took the test in 99, but I know it is pretty often.
I only looked in my mirrors for turning and passing and they took points off me for not checking my blind spots. I only partly remember because I got really bothered by it.
I think it's every two minutes or so. Not sure. I'd try to find out online. Just check often.