Headlight Relay Yes No

You don't need headlight relays if your headlamp switch is good (new ones are cheap), all connections (like in the bulkhead) are pristine, and using factory rated bulbs. A relay can be a kludge to get around those problems, but perhaps fixing the true problems is easier.

A relay may be necessary if high-load after-market HID lamps. If totally rewiring the under-hood, relays are certainly smart. As 67Dart273, I did that, installing a newish (95-99) underhood relay/fuse box in 2 of my old Mopars (black box in my avatar). In that case, I had plenty of relays so used one for low-beam and one for high-beam, plus replaced my factory starter and horn relays. I wouldn't kludge-on individual headlamp relays like the Frankenstein jobs some people show.