I HAVE owned a 1976 Ford F100 XLT since new. It is in good condition and fitted with a canopy, but I have noticed some rusting at the welds on the cabin and the door bases, which I guess would cost a fair bit to repair. Are F100s likely to become collectors' items and increase in value like cars, or is a truck just a truck with only a basic value.
IF YOU were talking about a '56 F100, then I would say it would increase in value. They're popular with hot rodders, but yours is unlikely to increase in value over time. It's not a highly sought-after model and, to be honest, I would drive it into the ground or get out of it before the rust overtakes it.