ProSeries (PS) should handle your garden variety tax depreciation and gain/loss just fine.  If you have to keep track of book depreciation and/or have state/local filings (i.e. personal property taxes) then you might want to use Fixed Asset Manager (FAM) to make your state reporting easier.

Either way FAM is not required.

If you enter assets directly in PS 2019, they will roll over into PS 2020 when you update the tax file.  Then you just enter your 2020 assets and you're done.

If you enter assets into FAM 2019 your process will be more like this:

1) Roll company files from FAM 2019 to FAM 2020.
2) "Close the year" for company files in FAM 2020 so that it will compute 2020 depreciation.
3) Enter 2020 assets into FAM.
4) Export FAM 2020 to an import file.
5) Import the file into PS 2020.

And that'll be for each client.

Here in VA we have to pay personal property tax (PPT) based on category and location.  So for a brick-n-mortar business with hundreds of fixed assets and/or locations in multiple counties/cities we need something to keep track of all this stuff.  So rather than have two systems running parallel it makes sense to use FAM to track the same assets for multiple reporting purposes.  Then export to PS for income taxes and print custom reports for property taxes.

If I didn't have the PPT aspect I wouldn't jump through the hoops required to use FAM, I would just leave the assets in PS.

Hope this helps.

Rick