The 1031 exchange rule to defer your tax is two part 1) reinvest all your proceeds and 2) purchase a property (or properties / DSTs/TICs) with an equal or greater market value.  

Keep in mind that you get to depreciate these appliances on your taxes.

I asked the tenant that he pay the 2nd plumbing fee of $79.

The problem with selling is a lot of that equity will be lost when you sell it either through taxes or payments to your listing agent.If you ever have the ability to limit these types of fees and still be able to use your equity to fund additional purchases I think you should.

This requires consistent oversight and experience, which most investors simply don’t have.The Bottom LineIf you want to lose money and risk expensive legal fees, go ahead and self-manage.

We did that for about 3 years until Jeff informed me he'd fallen behind on property taxes, and all of his lenders called the loans due.

It is what is left after snow removal, cutting the grass, utilities, tenant issues, parking lot issues, property taxes, mortgage payment, etc. that make a difference.

When we looked at what his cashflow is currently, and then considered what he would net out of a sale post tax, he decided to keep owning the properties.

If you can rent it for enough to cover the principal, interest, taxes and insurance and still put money in your pocket, plus cash flow on the property you're purchasing, that would be ideal.

You mentioned gross rents of $3400 per month and Principle/Interest/Tax/Insurance of $2500 per month.