Do you need an electrical panel upgrade for an EV charger?

Illustrative image, not a photo of a listed installer.
Short answer: not always. An installer should run a load calculation first. If your panel has spare capacity, a dedicated circuit may be enough. If it is full, old or unsafe, options can include a panel upgrade, a subpanel, or load management that shares capacity.
Do not accept a panel upgrade on a phone guess alone. Ask for the load calculation in writing and ask what cheaper options were ruled out, and why.