Final answer:
A gain on the sale of a depreciable asset means the asset was sold for more than its book value. Book value is calculated as the original cost minus accumulated depreciation. This does not imply anything about fair value, worth, or service life status.
Step-by-step explanation:
When a company reports a gain on the sale of a depreciable asset, the statement that is always true is that the company sold the asset for more than its book value. The book value of an asset is its original cost minus accumulated depreciation. If the selling price exceeds the book value, a gain is recorded. However, this does not necessarily relate to the asset's fair value or its worth, as those are subjective measures and can fluctuate based on market conditions and perceived value. Also, selling the asset before the end of its service life is not necessarily always true; an asset can be fully depreciated and still be in service.