@Jian Lin I would recommend starting with the Richest Man in Babylon, then Rich Dad Poor Dad, Millionaire Real Estate Investor, Atomic Habits and the Go Giver

I've made a habit (regardless if it's smart) to leave a few sections loose so we can access it without cutting up glued PVC pipes to clean out drains.

We don’t know any PMCs to recommend in the area mentioned, but since selecting the wrong PMC is usually more harmful than selecting a bad tenant, you might want to read our series about “How to Screen a PMC Better than a Tenant”:https://www.biggerpockets.com/member-blogs/3094/91877-how-to-screen-a-pmc-better-than-a-tenant-part-1-services-and-processesEven if someone give you a referral, don’t make the mistake of assuming the PMC will meet your expectations, just because they met the expectations of the referral source.We recommend you get management contracts from several PMCs and compare the services they cover and, more importantly, what they each DO NOT cover.

The best strategy depends on a few things:- current condition of the property: how much rehab (if any) is needed; vacant or occupied- highest and best use of the property- your long-term goals... and moreIf the property is habitable (or just needs a cosmetic facelift), I'd consider the BRRRR strategy.

There is no harm in double and triple checking. 

Its an idea that will backfire, and possibly cause harm to the tourism industry of PR. 

But it can do no harm in preparing for the moment i can get a loan!

As John pointed out, if these folks pay on time then I wouldn't worry so much about their cleaning (or lack of) habits.  

The outcome is a safe habitable duplex with tenants that seem willing to stay and limited capital expenditures for the near term.

We don’t know any PMCs to recommend in the area mentioned, but since selecting the wrong PMC is usually more harmful than selecting a bad tenant, you might want to read our series about “How to Screen a PMC Better than a Tenant”:https://www.biggerpockets.com/member-blogs/3094/91877-how-to-screen-a-pmc-better-than-a-tenant-part-1-services-and-processesWe recommend you get management contracts from several PMCs and compare the services they cover and, more importantly, what they each DO NOT cover.