Start by talking to your PM.

If it cost you $5000 to install, use that as your starting point.

My wife and I are starting our investment journey and have our heart set on Anna Maria Island for our first STR/BRRRR.

Hey @Jennifer Lopez, here is a spreadsheet you can start with that I used and have shared on BP for a long time. 

Just starting out.

So, whatever I decide needs to be VERY GOOD from the start!

Someone with one newer aged rental, who has a rather high income, such as a surgeon who lives alone comfortably with a lot of disposable income, could possibly carry less than a Mr and Mrs just starting out, with one rental that they bought as a turnkey in a more downtrodden neighborhood in a different state.

The key is start ASAP.   

Many owners use it as a resource once they start their search and come across the NARPM website.

If your why on investing in real estate is to make extra money, that's a start, but it's not the real why.