My current tenant is so angry at me and yelled at me.

I’M going to ask the question that many others will - why are you paying cash when money is so cheap?  

Having a low mortgage is so advantageous in itself. 

Rent is SO HIGH in Los Angeles that if you can cut down your living expense significantly, you're way ahead.

At your suggestion I did find the BP calculators and that is SO helpful!

The NPV (net present value) needs to be predicted alongside the assumptions of appreciation. 30 years is so far away (the last 6 months during CoVid feels like it has been 15 years)!

The data is so muddled with banks that pre-emptively signed up their entire portfolio for forbearance assistance whether or not they needed it that's included in this data.

Shop early, shop focused, use contingencies if possible, Get the replacement property under contract before the sale closes, develop a team out of your immediate region, and lastly use back ups like pocket listings or passive fractional products.45 days seems like it is so short to identify your replacements @Dan Powers. 

Being a listing agent is so much more than a sign in the yard.

Unless the tenant leaves which if their rent is so low they'll be in no hurry, even with small incremental rent raises.