I'll add my data to the pool here. 2012 Glee that lost headlights at just over 71k. Checked a lot of things - voltage was fine, but seemed like not enough current was getting through. All connectors looked fine, some slight corrosion on the contacts in the starter switch. Cleaned up, covered with dielectric grease, headlights working again. It should be noted that I switched to H4 LED drop-in bulbs very early on, which draw about a third of the power, if not less, of standard incandescent bulbs. That's one of the reasons I never bothered putting the harness on, but...we'll see how I get on.
2013 Triumph Street Triple R
2012 Suzuki V-Strom 650