You haven't ridden enough if ya think ya don't need the RH mirror
If you ride in the bike lane like a bicycle and follow all the bicycle rules you should be fine with only the LH mirror
LH/RH mirrors of course. I use em both.
When getting in the left lane ya want to see what's coming up behind you in the right lane
4 lane Roads are common here in CA.
Besides the RH mirror lets ya see more directly behind you and the LH mirror allows ya to to see more to the left while still seeing behind you There's more reassurance and ya don't have to look over your right shoulder in those instances when ya need to.
But of course when changing lanes check your mirrors and look to the side so you can see if anything is in your blind spot
In some states the Moped and M/C Law says ya just need the LH mirror. While other states say ya need the RH and LH side mirrors
I've got just the LH mirror on my E bike and it's OK since I don't go over 25 MPH stay in the bike lane. - Class 2 E Bike
Besides with my E Bike I'm usually off road because that's where the fun is at