@penny1734 wrote:
I think I should file amended returns for 2018 to take depreciation for 2018.
That would actually be counter to the established procedure for rectifying the failure to take depreciation deductions over two or more tax years.
If you are going to amend your 2018 return, then you also need to file Form 3115 since you used an improper method of accounting in previous years. The alternative would be to do nothing and file Form 3115 with your 2019 income tax return.
