You can make your own: To make buttermilk, use 1 cup milk and 1 tablespoon lemon juice or white vinegar. Allow it to sit for a few minutes. If you do purchase buttermilk and have extra, freeze it in 1 cup containers or in Ziplock bags. You can also purchase powdered buttermilk in grocery stores.
Straight-line depreciation allows an equal portion of the laptop's cost to be claimed in each year over the total depreciation period. If the cost of the computer was $1,000, for example, then $200 a year can be included in the company's total depreciation amount each year for five years.
For example, it will take 10 years to depreciate the asset net book value to $20,604.7 (i.e., $604.7 more than the salvage value) and 25 years to depreciate it to $20,000.28 (i.e., $0.28 than the salvage value). Ten and 25 years periods are much longer than the estimated useful life of the asset.