Are occasional vertigo attacks, maybe once year or every few years, anything to worry about?

Vertigo is common: Vertigo is a common symptom and there are many remedies. Have you tried home Epley manuevers to help? By itself, vertigo, the sensation of movement when you are not moving, is rarely a serious symptom. Although the internet may say otherwise, most people have a very good outcome.

Yes and no: A wide variety of possible explanations exist. First it has to be clarified if vertigo or light-headedness. Associated symptoms are important to know. Vestibular migraines, meniere's, viral labrynthitis, other migraine variants are among the possbilities. An ENT or neurology physician who takes a good history is a good place to start.