You're right in that there's no way to really know for sure before you make the purchase. Although the issue seems more pronounced for some years (and owners) than others, there are very few people who would say their truck burns ZERO oil between changes. The key, as circmand said, is to check it as often as possible and keep a spare quart or two with you at all times. So I wouldn't consider the degree of oil consumption as a differentiating factor when you're looking to buy.
If you stay on top of it the oil consumption issue is really more of a nuisance than anything else.