Calculating ROI Before Purchase, During Rental, and After Selling

[Leslie Hsia]

New investor here. I'm trying to learn/understand when to use different types of ROI. I'd like to get some of my learnings validated here and also have some questions answered as to how I should interpret some other types (like IRR). My investment objective for rental properties is cash flow (and not so much appreciation).

In terms of understanding total annualized ROI for a rental property (assuming I already bought it and have been renting it out for some time), my understanding of Total ROI is the following:

Total ROI = (Net Selling Price + Total Cash Flow) / (Total Investment Amount), with Total Investment Amount and Total Cash Flow adjusted for inflation.

I would then annualize the Total ROI figure by performing the following: Annualized Total ROI = (1 + Total ROI) ^ (1/(Years Held)) - 1

Now, assuming that I'm running numbers PRIOR to purchasing a rental property, I've been reading a lot about IRR. The issue that I run into is that I don't have any gauge as to what my future cash flow will be. Given that IRR doesn't include inflation, my best guess is that my annual cash flow this year will be the same as any other year. If this is the case, then what difference does it make if I were to just use the Total Annualized ROI equation described above (factoring out the selling price assuming I don't plan on selling the property in the future)? aka what's the difference that Total Annualized ROI figure vs IRR (other than the fact that I included Selling Price in one of them)?

And lastly, let's say I bought a rental property and I've been renting it out for 10 years. Which ROI (or ROI's) would you use to determine if you should sell today or sell in the next 10 years? I'm having trouble combining the effects of inflation that has already occurred vs what your anticipation for the future is.

Thanks in advance!