I do. Even when the diagnosis code is side-specific, I still occasionally have denials for missing modifier for anatomical site.

If the diagnosis code is not side specific, I definitely always add the side for unilateral procedures. For instance, we do facet joint injections for pain management. If the patient has spondylosis (arthritis) of the spine (for which the diagnosis code doesn’t specify sides), their insurance may only allow a certain number of procedures per calendar year, so it’s important to designate which side we’re doing the procedure on so that if they have another set done on the other side, the insurance knows its not a duplicate of the last procedure.

I definitely don’t think it ever hurts to have a LT or RT modifier if one is appropriate!