I used to work as a fleet mechanic for some years. I found that the Motorcraft parts lasted the best. I bought all different brands of parts but had the best life expectancy out of Motorcraft parts.
It sounds like your belts are glazed. You can tell by looking at it in the light. If it has a shiny look to it, it is glazed. This usually isn't a problem, but it can make some noise. Lubricating the belt is temporary, but changing it is semi-permanent. If you find you're going through a lot of belts you'll want to look at your pulleys and maybe your tensioner.
1997 F-150, 4.6, automatic, Dark Toreador Red, Supercab, Flareside, 4X4 Off-Road, Towing Package, Ford hvy dty rubber floor mats, Chrome Grizzly Wrap Around Push Bar with 2 KC 100w Daylighters, Ventshades, Ford bedliner, Code Alarm Sure Start RVS remote starter, Ford alarm, Realistic CB with Wilson Little Wil antenna and Astatic power mic, ported MAF sensor, and Lots of TLC!! (Besides being an F-150 nut, I am a Ford auto technician.)