First, while I always like to know what the tax benefits are of my properties, I rarely factor the financial benefit into my return calculations when trying to determine if I will do the deal. The main reason for this is that most tax benefits will be recaptured at the end of the deal, so the benefit is not quite as good as it may seem.
To be more specific, consider the situation where you get a lump sum of $5,000 back at the end of the year (or avoid paying $5,000) thanks to depreciation. Given that you will likely have to pay that $5,000 at some point in the future, the benefit is the arbitrage you get from time value of money. Basically, how much can you earn from that $5,000 between the time you save it and have to pay it back.
Factoring this into your returns is probably more difficult than it's worth. At least for single family and smaller properties. Now, if you are doing larger properties where the tax savings are in the six or seven figures, and you have the ability to push that savings out over decades instead of years, then or may be worth the time to factor that into your returns.
There's a simple way to do this and a more complex way. The simple way is that you take the year one or annual savings and you factor that into your cash on cash return for that year. If it's bonus depreciation, it will give you a nice COC bump for a single year, so don't be confused into thinking that's going to be every year.
The more complex, but more accurate way to do this is exactly what I said above. Do a time value of money calculation (PV calculation) on the money you'd save between tax benefit and recapture and add that to the equity that the property would generate for you.
Personally, I treat tax benefits similar to natural appreciation. I don't assume I'm going to get any or that it will be valuable to me, but I know that anything I do get is a bonus and will make my numbers better than what my analysis has indicated.
I just rolled out of bed, so if that's not coherent, let me know and I'm happy to explain further. 🙂