I assume this is for a business you own. If not, let us know please.
Assets valued at less than $2500 can be expensed as a general business expense. You don't have to list them separately as an asset unless you want to. I don't recommend it for anything less than $2500, because depending on the class life of the asset, the yearly depreciation makes absolutely no difference on your tax liability. But when you "dispose" of that asset and recapture the depreciation as required by law, chances are that *will* impact your tax liability and you'll pay more in taxes.
So overall if you have an asset that is less than $2500, I recommend you just expense it, and not capitalize and depreciate it.
Otherwise if you want to depreciate it, you can. If you like group all items that were placed "in service" on the same date, as a single asset (such as "tools" for example) and do it that way. But grouping tools together can present it own problems in the future. If say next year you lose or break one of the tools in your group, that means you have to do the paperwork to change the cost basis of the asset, plus account for the percentage of the depreication already taken that applies to that one specific tool in the group that was taken out of service. It can become a nightmare quite easily.
Bottom line? I recommend you expense your tools in the tax year as your purchase them, if allowed.
