“My company’s equipment has been fully depreciated. But they can still function. What should we do?” A fully depreciated

[answerhappygod]

“My company’s equipment has been fully depreciated. But they can
still function. What should we do?”
A fully depreciated equipment means that the accumulated
depreciation has reached the full depreciable basis (acquisition
cost-salvage value). If this occurs, before the firm disposes the
fully depreciated equipment, it will remain on balance sheet, with
the cost and accumulated depreciation. But the firm can’t recognize
any depreciation expense on income statement anymore related to
this equipment.
The reason it happened was because the firm made a mistake in
the estimating the useful life of the equipment and didn’t
reevaluate this assumption annually as suggested by FASB. More
importantly, how does this affect the relevance of the information
provided to the investors? To discuss this, you may talk about from
the following perspectives: